demos/cube.cpp

/*
* Copyright (c) 2015-2016 The Khronos Group Inc.
* Copyright (c) 2015-2016 Valve Corporation
* Copyright (c) 2015-2016 LunarG, Inc.
*
* Licensed under the Apache License, Version 2.0 (the "License");
* you may not use this file except in compliance with the License.
* You may obtain a copy of the License at
*
*     http://www.apache.org/licenses/LICENSE-2.0
*
* Unless required by applicable law or agreed to in writing, software
* distributed under the License is distributed on an "AS IS" BASIS,
* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
* See the License for the specific language governing permissions and
* limitations under the License.
*
* Author: Jeremy Hayes <jeremy@lunarg.com>
*/

#if defined(VK_USE_PLATFORM_XLIB_KHR) || defined(VK_USE_PLATFORM_XCB_KHR)
#include <X11/Xutil.h>
#endif

#include <cassert>
#include <cstdio>
#include <cstdlib>
#include <cstring>
#include <csignal>
#include <memory>

#define VULKAN_HPP_NO_EXCEPTIONS
#include <vulkan/vulkan.hpp>
#include <vulkan/vk_sdk_platform.h>

#include "linmath.h"

#ifndef NDEBUG
#define VERIFY(x) assert(x)
#else
#define VERIFY(x) ((void)(x))
#endif

#define APP_SHORT_NAME "cube"
#ifdef _WIN32
#define APP_NAME_STR_LEN 80
#endif

// Allow a maximum of two outstanding presentation operations.
#define FRAME_LAG 2

#define ARRAY_SIZE(a) (sizeof(a) / sizeof(a[0]))

#ifdef _WIN32
#define ERR_EXIT(err_msg, err_class)                                           \
    do {                                                                       \
        if (!suppress_popups)                                                  \
            MessageBox(nullptr, err_msg, err_class, MB_OK);                    \
        exit(1);                                                               \
    } while (0)
#else
#define ERR_EXIT(err_msg, err_class)                                           \
    do {                                                                       \
        printf(err_msg);                                                       \
        fflush(stdout);                                                        \
        exit(1);                                                               \
    } while (0)
#endif

struct texture_object
{
    vk::Sampler sampler;

    vk::Image image;
    vk::ImageLayout imageLayout;

    vk::MemoryAllocateInfo mem_alloc;
    vk::DeviceMemory mem;
    vk::ImageView view;

    int32_t tex_width;
    int32_t tex_height;
};

static char const*const tex_files[] = {"lunarg.ppm"};

static int validation_error = 0;

struct vkcube_vs_uniform {
    // Must start with MVP
    float mvp[4][4];
    float position[12 * 3][4];
    float color[12 * 3][4];
};

struct vktexcube_vs_uniform {
    // Must start with MVP
    float mvp[4][4];
    float position[12 * 3][4];
    float attr[12 * 3][4];
};

//--------------------------------------------------------------------------------------
// Mesh and VertexFormat Data
//--------------------------------------------------------------------------------------
// clang-format off
static const float g_vertex_buffer_data[] = {
    -1.0f,-1.0f,-1.0f,  // -X side
    -1.0f,-1.0f, 1.0f,
    -1.0f, 1.0f, 1.0f,
    -1.0f, 1.0f, 1.0f,
    -1.0f, 1.0f,-1.0f,
    -1.0f,-1.0f,-1.0f,

    -1.0f,-1.0f,-1.0f,  // -Z side
     1.0f, 1.0f,-1.0f,
     1.0f,-1.0f,-1.0f,
    -1.0f,-1.0f,-1.0f,
    -1.0f, 1.0f,-1.0f,
     1.0f, 1.0f,-1.0f,

    -1.0f,-1.0f,-1.0f,  // -Y side
     1.0f,-1.0f,-1.0f,
     1.0f,-1.0f, 1.0f,
    -1.0f,-1.0f,-1.0f,
     1.0f,-1.0f, 1.0f,
    -1.0f,-1.0f, 1.0f,

    -1.0f, 1.0f,-1.0f,  // +Y side
    -1.0f, 1.0f, 1.0f,
     1.0f, 1.0f, 1.0f,
    -1.0f, 1.0f,-1.0f,
     1.0f, 1.0f, 1.0f,
     1.0f, 1.0f,-1.0f,

     1.0f, 1.0f,-1.0f,  // +X side
     1.0f, 1.0f, 1.0f,
     1.0f,-1.0f, 1.0f,
     1.0f,-1.0f, 1.0f,
     1.0f,-1.0f,-1.0f,
     1.0f, 1.0f,-1.0f,

    -1.0f, 1.0f, 1.0f,  // +Z side
    -1.0f,-1.0f, 1.0f,
     1.0f, 1.0f, 1.0f,
    -1.0f,-1.0f, 1.0f,
     1.0f,-1.0f, 1.0f,
     1.0f, 1.0f, 1.0f,
};

static const float g_uv_buffer_data[] = {
    0.0f, 1.0f,  // -X side
    1.0f, 1.0f,
    1.0f, 0.0f,
    1.0f, 0.0f,
    0.0f, 0.0f,
    0.0f, 1.0f,

    1.0f, 1.0f,  // -Z side
    0.0f, 0.0f,
    0.0f, 1.0f,
    1.0f, 1.0f,
    1.0f, 0.0f,
    0.0f, 0.0f,

    1.0f, 0.0f,  // -Y side
    1.0f, 1.0f,
    0.0f, 1.0f,
    1.0f, 0.0f,
    0.0f, 1.0f,
    0.0f, 0.0f,

    1.0f, 0.0f,  // +Y side
    0.0f, 0.0f,
    0.0f, 1.0f,
    1.0f, 0.0f,
    0.0f, 1.0f,
    1.0f, 1.0f,

    1.0f, 0.0f,  // +X side
    0.0f, 0.0f,
    0.0f, 1.0f,
    0.0f, 1.0f,
    1.0f, 1.0f,
    1.0f, 0.0f,

    0.0f, 0.0f,  // +Z side
    0.0f, 1.0f,
    1.0f, 0.0f,
    0.0f, 1.0f,
    1.0f, 1.0f,
    1.0f, 0.0f,
};

typedef struct
{
    vk::Image image;
    vk::CommandBuffer cmd;
    vk::CommandBuffer graphics_to_present_cmd;
    vk::ImageView view;
} SwapchainBuffers;

#ifdef _WIN32
// MS-Windows event handling function:
LRESULT CALLBACK WndProc(HWND hWnd, UINT uMsg, WPARAM wParam, LPARAM lParam);
#endif

struct Demo
{
    Demo() :
#if defined(VK_USE_PLATFORM_WIN32_KHR)
        connection{nullptr},
        window{nullptr},
        minsize(POINT{0, 0}), // Use explicit construction to avoid MSVC error C2797.
#elif defined(VK_USE_PLATFORM_XLIB_KHR) || defined(VK_USE_PLATFORM_XCB_KHR)
        display{nullptr},
        xlib_window{0},
        xlib_wm_delete_window{0},
        connection{nullptr},
        screen{nullptr},
        xcb_window{0},
        atom_wm_delete_window{nullptr},
#elif defined(VK_USE_PLATFORM_WAYLAND_KHR)
        display{nullptr},
        registry{nullptr},
        compositor{nullptr},
        window{nullptr},
        shell{nullptr},
        shell_surface{nullptr},
#endif
        prepared{false},
        use_staging_buffer{false},
        use_xlib{false},
        graphics_queue_family_index{0},
        present_queue_family_index{0},
        enabled_extension_count{0},
        enabled_layer_count{0},
        width{0},
        height{0},
        swapchainImageCount{0},
        frame_index{0},
        spin_angle{0.0f},
        spin_increment{0.0f},
        pause{false},
        quit{false},
        curFrame{0},
        frameCount{0},
        validate{false},
        use_break{false},
        suppress_popups{false},
        current_buffer{0},
        queue_family_count{0}
    {
#if defined(VK_USE_PLATFORM_WIN32_KHR)
        memset(name, '\0', APP_NAME_STR_LEN);
#elif defined(VK_USE_PLATFORM_XLIB_KHR) || defined(VK_USE_PLATFORM_XCB_KHR)
#elif defined(VK_USE_PLATFORM_WAYLAND_KHR)
#endif
        memset(fencesInited, 0, sizeof(bool)*FRAME_LAG);
        memset(projection_matrix, 0, sizeof(projection_matrix));
        memset(view_matrix, 0, sizeof(view_matrix));
        memset(model_matrix, 0, sizeof(model_matrix));
    }

    void build_image_ownership_cmd(uint32_t const& i)
    {
        auto const cmd_buf_info = vk::CommandBufferBeginInfo()
            .setFlags(vk::CommandBufferUsageFlagBits::eSimultaneousUse);
        auto result = buffers[i].graphics_to_present_cmd.begin(&cmd_buf_info);
        VERIFY(result == vk::Result::eSuccess);

        auto const image_ownership_barrier = vk::ImageMemoryBarrier()
            .setSrcAccessMask(vk::AccessFlags())
            .setDstAccessMask(vk::AccessFlagBits::eColorAttachmentWrite)
            .setOldLayout(vk::ImageLayout::ePresentSrcKHR)
            .setNewLayout(vk::ImageLayout::ePresentSrcKHR)
            .setSrcQueueFamilyIndex(graphics_queue_family_index)
            .setDstQueueFamilyIndex(present_queue_family_index)
            .setImage(buffers[i].image)
            .setSubresourceRange(vk::ImageSubresourceRange(vk::ImageAspectFlagBits::eColor, 0, 1, 0, 1));

        buffers[i].graphics_to_present_cmd.pipelineBarrier(vk::PipelineStageFlagBits::eColorAttachmentOutput,
             vk::PipelineStageFlagBits::eColorAttachmentOutput, vk::DependencyFlagBits(), 0, nullptr, 0, nullptr, 1,
             &image_ownership_barrier);

        result = buffers[i].graphics_to_present_cmd.end();
        VERIFY(result == vk::Result::eSuccess);
    }

    vk::Bool32 check_layers(uint32_t check_count, char const*const*const check_names, uint32_t layer_count,
        vk::LayerProperties *layers)
    {
        for(uint32_t i = 0; i < check_count; i++)
        {
            vk::Bool32 found = VK_FALSE;
            for(uint32_t j = 0; j < layer_count; j++)
            {
                if(!strcmp(check_names[i], layers[j].layerName))
                {
                    found = VK_TRUE;
                    break;
                }
            }
            if(!found)
            {
                fprintf(stderr, "Cannot find layer: %s\n", check_names[i]);
                return 0;
            }
        }
        return VK_TRUE;
    }

    void cleanup()
    {
        prepared = false;
        device.waitIdle();

        // Wait for fences from present operations
        for(uint32_t i = 0; i < FRAME_LAG; i++)
        {
            if(fencesInited[i])
            {
                device.waitForFences(1, &fences[i], VK_TRUE, UINT64_MAX);
            }
            device.destroyFence(fences[i], nullptr);
            device.destroySemaphore(image_acquired_semaphores[i], nullptr);
            device.destroySemaphore(draw_complete_semaphores[i], nullptr);
            if(separate_present_queue)
            {
                device.destroySemaphore(image_ownership_semaphores[i], nullptr);
            }
        }

        for(uint32_t i = 0; i < swapchainImageCount; i++)
        {
            device.destroyFramebuffer(framebuffers[i], nullptr);
        }
        device.destroyDescriptorPool(desc_pool, nullptr);

        device.destroyPipeline(pipeline, nullptr);
        device.destroyPipelineCache(pipelineCache, nullptr);
        device.destroyRenderPass(render_pass, nullptr);
        device.destroyPipelineLayout(pipeline_layout, nullptr);
        device.destroyDescriptorSetLayout(desc_layout, nullptr);

        for(uint32_t i = 0; i < texture_count; i++)
        {
            device.destroyImageView(textures[i].view, nullptr);
            device.destroyImage(textures[i].image, nullptr);
            device.freeMemory(textures[i].mem, nullptr);
            device.destroySampler(textures[i].sampler, nullptr);
        }
        device.destroySwapchainKHR(swapchain, nullptr);

        device.destroyImageView(depth.view, nullptr);
        device.destroyImage(depth.image, nullptr);
        device.freeMemory(depth.mem, nullptr);

        device.destroyBuffer(uniform_data.buf, nullptr);
        device.freeMemory(uniform_data.mem, nullptr);

        for(uint32_t i = 0; i < swapchainImageCount; i++)
        {
            device.destroyImageView(buffers[i].view, nullptr);
            device.freeCommandBuffers(cmd_pool, 1, &buffers[i].cmd);
        }

        device.destroyCommandPool(cmd_pool, nullptr);

        if(separate_present_queue)
        {
            device.destroyCommandPool(present_cmd_pool, nullptr);
        }

        device.destroy(nullptr);
        inst.destroySurfaceKHR(surface, nullptr);
        inst.destroy(nullptr);

#if defined(VK_USE_PLATFORM_XLIB_KHR) || defined(VK_USE_PLATFORM_XCB_KHR)
        if(use_xlib)
        {
            XDestroyWindow(display, xlib_window);
            XCloseDisplay(display);
        }
        else
        {
            xcb_destroy_window(connection, xcb_window);
            xcb_disconnect(connection);
        }
        free(atom_wm_delete_window);
#elif defined(VK_USE_PLATFORM_WAYLAND_KHR)
        wl_shell_surface_destroy(shell_surface);
        wl_surface_destroy(window);
        wl_shell_destroy(shell);
        wl_compositor_destroy(compositor);
        wl_registry_destroy(registry);
        wl_display_disconnect(display);
#endif
    }

    void create_device()
    {
        float const priorities[1] = {0.0};

        vk::DeviceQueueCreateInfo queues[2];
        queues[0].setQueueFamilyIndex(graphics_queue_family_index);
        queues[0].setQueueCount(1);
        queues[0].setPQueuePriorities(priorities);

        auto deviceInfo = vk::DeviceCreateInfo()
            .setQueueCreateInfoCount(1)
            .setPQueueCreateInfos(queues)
            .setEnabledLayerCount(0)
            .setPpEnabledLayerNames(nullptr)
            .setEnabledExtensionCount(enabled_extension_count)
            .setPpEnabledExtensionNames((const char *const *)extension_names)
            .setPEnabledFeatures(nullptr);

        if(separate_present_queue)
        {
            queues[1].setQueueFamilyIndex(present_queue_family_index);
            queues[1].setQueueCount(1);
            queues[1].setPQueuePriorities(priorities);
            deviceInfo.setQueueCreateInfoCount(2);
        }

        auto result = gpu.createDevice(&deviceInfo, nullptr, &device);
        VERIFY(result == vk::Result::eSuccess);
    }

    void destroy_texture_image(texture_object *tex_objs)
    {
        // clean up staging resources
        device.freeMemory(tex_objs->mem, nullptr);
        device.destroyImage(tex_objs->image, nullptr);
    }

    void draw()
    {
        if(fencesInited[frame_index])
        {
            // Ensure no more than FRAME_LAG presentations are outstanding
            device.waitForFences(1, &fences[frame_index], VK_TRUE, UINT64_MAX);
            device.resetFences(1, &fences[frame_index]);
        }

        // Get the index of the next available swapchain image:
        auto result = device.acquireNextImageKHR(swapchain, UINT64_MAX, image_acquired_semaphores[frame_index], fences[frame_index],
            &current_buffer);
        fencesInited[frame_index] = true;
        if(result == vk::Result::eErrorOutOfDateKHR)
        {
            // swapchain is out of date (e.g. the window was resized) and
            // must be recreated:
            frame_index += 1;
            frame_index %= FRAME_LAG;

            resize();
            draw();
            return;
        }
        else if(result == vk::Result::eSuboptimalKHR)
        {
            // swapchain is not as optimal as it could be, but the platform's
            // presentation engine will still present the image correctly.
        }
        else
        {
            VERIFY(result == vk::Result::eSuccess);
        }

        // Wait for the image acquired semaphore to be signaled to ensure
        // that the image won't be rendered to until the presentation
        // engine has fully released ownership to the application, and it is
        // okay to render to the image.
        vk::PipelineStageFlags const pipe_stage_flags = vk::PipelineStageFlagBits::eColorAttachmentOutput;
        auto const submit_info = vk::SubmitInfo()
            .setPWaitDstStageMask(&pipe_stage_flags)
            .setWaitSemaphoreCount(1)
            .setPWaitSemaphores(&image_acquired_semaphores[frame_index])
            .setCommandBufferCount(1)
            .setPCommandBuffers(&buffers[current_buffer].cmd)
            .setSignalSemaphoreCount(1)
            .setPSignalSemaphores(&draw_complete_semaphores[frame_index]);

        result = graphics_queue.submit(1, &submit_info, vk::Fence());
        VERIFY(result == vk::Result::eSuccess);

        if(separate_present_queue)
        {
            // If we are using separate queues, change image ownership to the
            // present queue before presenting, waiting for the draw complete
            // semaphore and signalling the ownership released semaphore when finished
            auto const submit_info = vk::SubmitInfo()
                .setPWaitDstStageMask(&pipe_stage_flags)
                .setWaitSemaphoreCount(1)
                .setPWaitSemaphores(&draw_complete_semaphores[frame_index])
                .setCommandBufferCount(1)
                .setPCommandBuffers(&buffers[current_buffer].graphics_to_present_cmd)
                .setSignalSemaphoreCount(1)
                .setPSignalSemaphores(&image_ownership_semaphores[frame_index]);

            result  = present_queue.submit(1, &submit_info, vk::Fence());
            VERIFY(result == vk::Result::eSuccess);
        }

        // If we are using separate queues we have to wait for image ownership,
        // otherwise wait for draw complete
        auto const presentInfo = vk::PresentInfoKHR()
            .setWaitSemaphoreCount(1)
            .setPWaitSemaphores(separate_present_queue ?
                &image_ownership_semaphores[frame_index] : &draw_complete_semaphores[frame_index])
            .setSwapchainCount(1)
            .setPSwapchains(&swapchain)
            .setPImageIndices(&current_buffer);

        result = present_queue.presentKHR(&presentInfo);
        frame_index += 1;
        frame_index %= FRAME_LAG;
        if(result == vk::Result::eErrorOutOfDateKHR)
        {
            // swapchain is out of date (e.g. the window was resized) and
            // must be recreated:
            resize();
        }
        else if(result == vk::Result::eSuboptimalKHR)
        {
            // swapchain is not as optimal as it could be, but the platform's
            // presentation engine will still present the image correctly.
        }
        else
        {
            VERIFY(result == vk::Result::eSuccess);
        }
    }

    void draw_build_cmd(vk::CommandBuffer commandBuffer)
    {
        auto const commandInfo = vk::CommandBufferBeginInfo()
            .setFlags(vk::CommandBufferUsageFlagBits::eSimultaneousUse);

        vk::ClearValue const clearValues[2] =
        {
            vk::ClearColorValue(std::array<float, 4>({ 0.2f, 0.2f, 0.2f, 0.2f })),
            vk::ClearDepthStencilValue(1.0f, 0u)
        };

        auto const passInfo = vk::RenderPassBeginInfo()
            .setRenderPass(render_pass)
            .setFramebuffer(framebuffers[current_buffer])
            .setRenderArea(vk::Rect2D(vk::Offset2D(0, 0), vk::Extent2D((uint32_t)width, (uint32_t)height)))
            .setClearValueCount(2)
            .setPClearValues(clearValues);

        auto result = commandBuffer.begin(&commandInfo);
        VERIFY(result == vk::Result::eSuccess);

        auto const image_memory_barrier = vk::ImageMemoryBarrier()
            .setSrcAccessMask(vk::AccessFlagBits::eMemoryRead)
            .setDstAccessMask(vk::AccessFlagBits::eColorAttachmentWrite)
            .setOldLayout(vk::ImageLayout::ePresentSrcKHR)
            .setNewLayout(vk::ImageLayout::eColorAttachmentOptimal)
            .setSrcQueueFamilyIndex(VK_QUEUE_FAMILY_IGNORED)
            .setDstQueueFamilyIndex(VK_QUEUE_FAMILY_IGNORED)
            .setImage(buffers[current_buffer].image)
            .setSubresourceRange(vk::ImageSubresourceRange(vk::ImageAspectFlagBits::eColor, 0, 1, 0, 1));

        commandBuffer.pipelineBarrier(vk::PipelineStageFlagBits::eColorAttachmentOutput,
            vk::PipelineStageFlagBits::eColorAttachmentOutput, vk::DependencyFlagBits(), 0, nullptr, 0, nullptr, 1,
            &image_memory_barrier);

        commandBuffer.beginRenderPass(&passInfo, vk::SubpassContents::eInline);

        commandBuffer.bindPipeline(vk::PipelineBindPoint::eGraphics, pipeline);
        commandBuffer.bindDescriptorSets(vk::PipelineBindPoint::eGraphics, pipeline_layout,
            0, 1, &desc_set,
            0, nullptr);

        auto const viewport = vk::Viewport()
            .setWidth((float)width)
            .setHeight((float)height)
            .setMinDepth((float)0.0f)
            .setMaxDepth((float)1.0f);
        commandBuffer.setViewport(0, 1, &viewport);

        vk::Rect2D const scissor(vk::Offset2D(0, 0), vk::Extent2D(width, height));
        commandBuffer.setScissor(0, 1, &scissor);
        commandBuffer.draw(12 * 3, 1, 0, 0);
        // Note that ending the renderpass changes the image's layout from
        // COLOR_ATTACHMENT_OPTIMAL to PRESENT_SRC_KHR
        commandBuffer.endRenderPass();

        if(separate_present_queue)
        {
            // We have to transfer ownership from the graphics queue family to the
            // present queue family to be able to present.  Note that we don't have
            // to transfer from present queue family back to graphics queue family at
            // the start of the next frame because we don't care about the image's
            // contents at that point.
            auto const image_ownership_barrier = vk::ImageMemoryBarrier()
                .setSrcAccessMask(vk::AccessFlags())
                .setDstAccessMask(vk::AccessFlagBits::eColorAttachmentWrite)
                .setOldLayout(vk::ImageLayout::ePresentSrcKHR)
                .setNewLayout(vk::ImageLayout::ePresentSrcKHR)
                .setSrcQueueFamilyIndex(graphics_queue_family_index)
                .setDstQueueFamilyIndex(present_queue_family_index)
                .setImage(buffers[current_buffer].image)
                .setSubresourceRange(vk::ImageSubresourceRange(vk::ImageAspectFlagBits::eColor, 0, 1, 0, 1));

            commandBuffer.pipelineBarrier(vk::PipelineStageFlagBits::eColorAttachmentOutput,
                vk::PipelineStageFlagBits::eColorAttachmentOutput, vk::DependencyFlagBits(), 0, nullptr, 0, nullptr, 1,
                &image_ownership_barrier);
        }

        result = commandBuffer.end();
        VERIFY(result == vk::Result::eSuccess);
    }

    void flush_init_cmd()
    {
        // TODO: hmm.
        // This function could get called twice if the texture uses a staging buffer
        // In that case the second call should be ignored
        if(!cmd)
        {
            return;
        }

        auto result = cmd.end();
        VERIFY(result == vk::Result::eSuccess);

        auto const fenceInfo = vk::FenceCreateInfo()
            .setFlags(vk::FenceCreateFlagBits(0));
        vk::Fence fence;
        device.createFence(&fenceInfo, nullptr, &fence);

        vk::CommandBuffer const commandBuffers[] =
        {
            cmd
        };
        auto const submitInfo = vk::SubmitInfo()
            .setCommandBufferCount(1)
            .setPCommandBuffers(commandBuffers);

        result = graphics_queue.submit(1, &submitInfo, fence);
        VERIFY(result == vk::Result::eSuccess);

        result = device.waitForFences(1, &fence, VK_TRUE, UINT64_MAX);
        VERIFY(result == vk::Result::eSuccess);

        device.freeCommandBuffers(cmd_pool, 1, commandBuffers);
        device.destroyFence(fence, nullptr);

        cmd = vk::CommandBuffer();
    }

    void init(int argc, char **argv)
    {
        vec3 eye = {0.0f, 3.0f, 5.0f};
        vec3 origin = {0, 0, 0};
        vec3 up = {0.0f, 1.0f, 0.0};

        frameCount = UINT32_MAX;
        use_xlib = false;

        for (int i = 1; i < argc; i++) {
            if(strcmp(argv[i], "--use_staging") == 0)
            {
                use_staging_buffer = true;
                continue;
            }
            if(strcmp(argv[i], "--break") == 0)
            {
                use_break = true;
                continue;
            }
            if(strcmp(argv[i], "--validate") == 0)
            {
                validate = true;
                continue;
            }
#if defined(VK_USE_PLATFORM_XLIB_KHR)
            if(strcmp(argv[i], "--xlib") == 0)
            {
                use_xlib = true;
                continue;
            }
#endif
            if(strcmp(argv[i], "--c") == 0 && frameCount == UINT32_MAX &&
                i < argc - 1 && sscanf(argv[i + 1], "%d", &frameCount) == 1)
            {
                i++;
                continue;
            }
            if(strcmp(argv[i], "--suppress_popups") == 0)
            {
                suppress_popups = true;
                continue;
            }

            fprintf(stderr, "Usage:\n  %s [--use_staging] [--validate] [--break] "
#if defined(VK_USE_PLATFORM_XLIB_KHR)
                            "[--xlib] "
#endif
                            "[--c <framecount>] [--suppress_popups]\n",
                    APP_SHORT_NAME);
            fflush(stderr);
            exit(1);
        }

        if(!use_xlib)
        {
            init_connection();
        }

        init_vk();

        width = 500;
        height = 500;

        spin_angle = 4.0f;
        spin_increment = 0.2f;
        pause = false;

        mat4x4_perspective(projection_matrix, (float)degreesToRadians(45.0f),
                           1.0f, 0.1f, 100.0f);
        mat4x4_look_at(view_matrix, eye, origin, up);
        mat4x4_identity(model_matrix);

        projection_matrix[1][1]*=-1;  //Flip projection matrix from GL to Vulkan orientation.
    }

    void init_connection()
    {
#if defined(VK_USE_PLATFORM_XCB_KHR)
        const xcb_setup_t *setup;
        xcb_screen_iterator_t iter;
        int scr;

        connection = xcb_connect(nullptr, &scr);
        if(xcb_connection_has_error(connection) > 0)
        {
            printf("Cannot find a compatible Vulkan installable client driver "
                   "(ICD).\nExiting ...\n");
            fflush(stdout);
            exit(1);
        }

        setup = xcb_get_setup(connection);
        iter = xcb_setup_roots_iterator(setup);
        while(scr-- > 0)
            xcb_screen_next(&iter);

        screen = iter.data;
#elif defined(VK_USE_PLATFORM_WAYLAND_KHR)
        display = wl_display_connect(nullptr);

        if(display == nullptr)
        {
            printf("Cannot find a compatible Vulkan installable client driver "
                   "(ICD).\nExiting ...\n");
            fflush(stdout);
            exit(1);
        }

        registry = wl_display_get_registry(display);
        wl_registry_add_listener(registry, &registry_listener, this);
        wl_display_dispatch(display);
#endif
    }

    void init_vk()
    {
        uint32_t instance_extension_count = 0;
        uint32_t instance_layer_count = 0;
        uint32_t validation_layer_count = 0;
        char const*const* instance_validation_layers = nullptr;
        enabled_extension_count = 0;
        enabled_layer_count = 0;

        char const*const instance_validation_layers_alt1[] =
        {
            "VK_LAYER_LUNARG_standard_validation"
        };

        char const*const instance_validation_layers_alt2[] =
        {
            "VK_LAYER_GOOGLE_threading",
            "VK_LAYER_LUNARG_parameter_validation",
            "VK_LAYER_LUNARG_object_tracker",
            "VK_LAYER_LUNARG_image",
            "VK_LAYER_LUNARG_core_validation",
            "VK_LAYER_LUNARG_swapchain",
            "VK_LAYER_GOOGLE_unique_objects"
        };

        // Look for validation layers
        vk::Bool32 validation_found = VK_FALSE;
        if(validate)
        {
            auto result = vk::enumerateInstanceLayerProperties(&instance_layer_count, nullptr);
            VERIFY(result == vk::Result::eSuccess);

            instance_validation_layers = instance_validation_layers_alt1;
            if(instance_layer_count > 0)
            {
                std::unique_ptr<vk::LayerProperties[]> instance_layers(new vk::LayerProperties[instance_layer_count]);
                result = vk::enumerateInstanceLayerProperties(&instance_layer_count, instance_layers.get());
                VERIFY(result == vk::Result::eSuccess);

                validation_found = check_layers(ARRAY_SIZE(instance_validation_layers_alt1), instance_validation_layers,
                    instance_layer_count, instance_layers.get());
                if(validation_found)
                {
                    enabled_layer_count = ARRAY_SIZE(instance_validation_layers_alt1);
                    enabled_layers[0] = "VK_LAYER_LUNARG_standard_validation";
                    validation_layer_count = 1;
                }
                else
                {
                    // use alternative set of validation layers
                    instance_validation_layers = instance_validation_layers_alt2;
                    enabled_layer_count = ARRAY_SIZE(instance_validation_layers_alt2);
                    validation_found = check_layers(ARRAY_SIZE(instance_validation_layers_alt2), instance_validation_layers,
                        instance_layer_count, instance_layers.get());
                    validation_layer_count = ARRAY_SIZE(instance_validation_layers_alt2);
                    for (uint32_t i = 0; i < validation_layer_count; i++)
                    {
                        enabled_layers[i] = instance_validation_layers[i];
                    }
                }
            }

            if(!validation_found)
            {
                ERR_EXIT("vkEnumerateInstanceLayerProperties failed to find required validation layer.\n\n"
                    "Please look at the Getting Started guide for additional information.\n",
                    "vkCreateInstance Failure");
            }
        }

        /* Look for instance extensions */
        vk::Bool32 surfaceExtFound = VK_FALSE;
        vk::Bool32 platformSurfaceExtFound = VK_FALSE;
#if defined(VK_USE_PLATFORM_XLIB_KHR)
        vk::Bool32 xlibSurfaceExtFound = VK_FALSE;
#endif
        memset(extension_names, 0, sizeof(extension_names));

        auto result = vk::enumerateInstanceExtensionProperties(nullptr, &instance_extension_count, nullptr);
        VERIFY(result == vk::Result::eSuccess);

        if(instance_extension_count > 0)
        {
            std::unique_ptr<vk::ExtensionProperties[]> instance_extensions(new vk::ExtensionProperties[instance_extension_count]);
            result = vk::enumerateInstanceExtensionProperties(nullptr, &instance_extension_count, instance_extensions.get());
            VERIFY(result == vk::Result::eSuccess);

            for(uint32_t i = 0; i < instance_extension_count; i++)
            {
                if(!strcmp(VK_KHR_SURFACE_EXTENSION_NAME, instance_extensions[i].extensionName))
                {
                    surfaceExtFound = 1;
                    extension_names[enabled_extension_count++] = VK_KHR_SURFACE_EXTENSION_NAME;
                }
#if defined(VK_USE_PLATFORM_WIN32_KHR)
                if(!strcmp(VK_KHR_WIN32_SURFACE_EXTENSION_NAME, instance_extensions[i].extensionName))
                {
                    platformSurfaceExtFound = 1;
                    extension_names[enabled_extension_count++] = VK_KHR_WIN32_SURFACE_EXTENSION_NAME;
                }
#endif
#if defined(VK_USE_PLATFORM_XLIB_KHR)
                if(!strcmp(VK_KHR_XLIB_SURFACE_EXTENSION_NAME, instance_extensions[i].extensionName))
                {
                    platformSurfaceExtFound = 1;
                    xlibSurfaceExtFound = 1;
                    extension_names[enabled_extension_count++] = VK_KHR_XLIB_SURFACE_EXTENSION_NAME;
                }
#endif
#if defined(VK_USE_PLATFORM_XCB_KHR)
                if(!strcmp(VK_KHR_XCB_SURFACE_EXTENSION_NAME, instance_extensions[i].extensionName))
                {
                    platformSurfaceExtFound = 1;
                    extension_names[enabled_extension_count++] = VK_KHR_XCB_SURFACE_EXTENSION_NAME;
                }
#endif
#if defined(VK_USE_PLATFORM_WAYLAND_KHR)
                if(!strcmp(VK_KHR_WAYLAND_SURFACE_EXTENSION_NAME, instance_extensions[i].extensionName))
                {
                    platformSurfaceExtFound = 1;
                    extension_names[enabled_extension_count++] = VK_KHR_WAYLAND_SURFACE_EXTENSION_NAME;
                }
#endif
                assert(enabled_extension_count < 64);
            }
        }

        if(!surfaceExtFound)
        {
            ERR_EXIT("vkEnumerateInstanceExtensionProperties failed to find the " VK_KHR_SURFACE_EXTENSION_NAME " extension.\n\n"
                "Do you have a compatible Vulkan installable client driver (ICD) installed?\n"
                "Please look at the Getting Started guide for additional information.\n",
                "vkCreateInstance Failure");
        }

        if(!platformSurfaceExtFound)
        {
#if defined(VK_USE_PLATFORM_WIN32_KHR)
            ERR_EXIT("vkEnumerateInstanceExtensionProperties failed to find the " VK_KHR_WIN32_SURFACE_EXTENSION_NAME " extension.\n\n"
                "Do you have a compatible Vulkan installable client driver (ICD) installed?\n"
                "Please look at the Getting Started guide for additional information.\n",
                "vkCreateInstance Failure");
#elif defined(VK_USE_PLATFORM_XCB_KHR)
            ERR_EXIT("vkEnumerateInstanceExtensionProperties failed to find the " VK_KHR_XCB_SURFACE_EXTENSION_NAME " extension.\n\n"
                "Do you have a compatible Vulkan installable client driver (ICD) installed?\n"
                "Please look at the Getting Started guide for additional information.\n",
                "vkCreateInstance Failure");
#elif defined(VK_USE_PLATFORM_WAYLAND_KHR)
            ERR_EXIT("vkEnumerateInstanceExtensionProperties failed to find the " VK_KHR_WAYLAND_SURFACE_EXTENSION_NAME " extension.\n\n"
                "Do you have a compatible Vulkan installable client driver (ICD) installed?\n"
                "Please look at the Getting Started guide for additional information.\n",
                "vkCreateInstance Failure");
#endif
        }

#if defined(VK_USE_PLATFORM_XLIB_KHR)
        if(use_xlib && !xlibSurfaceExtFound)
        {
            ERR_EXIT("vkEnumerateInstanceExtensionProperties failed to find the " VK_KHR_XLIB_SURFACE_EXTENSION_NAME " extension.\n\n"
                "Do you have a compatible Vulkan installable client driver (ICD) installed?\n"
                "Please look at the Getting Started guide for additional information.\n",
                "vkCreateInstance Failure");
        }
#endif

        auto const app = vk::ApplicationInfo()
            .setPApplicationName(APP_SHORT_NAME)
            .setApplicationVersion(0)
            .setPEngineName(APP_SHORT_NAME)
            .setEngineVersion(0)
            .setApiVersion(VK_API_VERSION_1_0);
        auto const inst_info = vk::InstanceCreateInfo()
            .setPApplicationInfo(&app)
            .setEnabledLayerCount(enabled_layer_count)
            .setPpEnabledLayerNames(instance_validation_layers)
            .setEnabledExtensionCount(enabled_extension_count)
            .setPpEnabledExtensionNames(extension_names);

        result = vk::createInstance(&inst_info, nullptr, &inst);
        if(result == vk::Result::eErrorIncompatibleDriver)
        {
            ERR_EXIT("Cannot find a compatible Vulkan installable client driver (ICD).\n\n"
                "Please look at the Getting Started guide for additional information.\n",
                "vkCreateInstance Failure");
        }
        else if(result == vk::Result::eErrorExtensionNotPresent)
        {
            ERR_EXIT("Cannot find a specified extension library.\n"
                "Make sure your layers path is set appropriately.\n",
                "vkCreateInstance Failure");
        }
        else if(result != vk::Result::eSuccess)
        {
            ERR_EXIT("vkCreateInstance failed.\n\n"
                "Do you have a compatible Vulkan installable client driver (ICD) installed?\n"
                "Please look at the Getting Started guide for additional information.\n",
                "vkCreateInstance Failure");
        }

        /* Make initial call to query gpu_count, then second call for gpu info*/
        uint32_t gpu_count;
        result = inst.enumeratePhysicalDevices(&gpu_count, nullptr);
        VERIFY(result == vk::Result::eSuccess);
        assert(gpu_count > 0);

        if(gpu_count > 0)
        {
            std::unique_ptr<vk::PhysicalDevice[]> physical_devices(new vk::PhysicalDevice[gpu_count]);
            result = inst.enumeratePhysicalDevices(&gpu_count, physical_devices.get());
            VERIFY(result == vk::Result::eSuccess);
            /* For cube demo we just grab the first physical device */
            gpu = physical_devices[0];
        }
        else
        {
            ERR_EXIT("vkEnumeratePhysicalDevices reported zero accessible devices.\n\n"
                "Do you have a compatible Vulkan installable client driver (ICD) installed?\n"
                "Please look at the Getting Started guide for additional information.\n",
                "vkEnumeratePhysicalDevices Failure");
        }

        /* Look for device extensions */
        uint32_t device_extension_count = 0;
        vk::Bool32 swapchainExtFound = VK_FALSE;
        enabled_extension_count = 0;
        memset(extension_names, 0, sizeof(extension_names));

        result = gpu.enumerateDeviceExtensionProperties(nullptr, &device_extension_count, nullptr);
        VERIFY(result == vk::Result::eSuccess);

        if(device_extension_count > 0)
        {
            std::unique_ptr<vk::ExtensionProperties[]> device_extensions(new vk::ExtensionProperties[device_extension_count]);
            result = gpu.enumerateDeviceExtensionProperties(nullptr, &device_extension_count, device_extensions.get());
            VERIFY(result == vk::Result::eSuccess);

            for(uint32_t i = 0; i < device_extension_count; i++)
            {
                if(!strcmp(VK_KHR_SWAPCHAIN_EXTENSION_NAME, device_extensions[i].extensionName))
                {
                    swapchainExtFound = 1;
                    extension_names[enabled_extension_count++] = VK_KHR_SWAPCHAIN_EXTENSION_NAME;
                }
                assert(enabled_extension_count < 64);
            }
        }

        if(!swapchainExtFound)
        {
            ERR_EXIT("vkEnumerateDeviceExtensionProperties failed to find the " VK_KHR_SWAPCHAIN_EXTENSION_NAME " extension.\n\n"
                "Do you have a compatible Vulkan installable client driver (ICD) installed?\n"
                "Please look at the Getting Started guide for additional information.\n",
                "vkCreateInstance Failure");
        }

        gpu.getProperties(&gpu_props);

        /* Call with nullptr data to get count */
        gpu.getQueueFamilyProperties(&queue_family_count, nullptr);
        assert(queue_family_count >= 1);

        queue_props.reset(new vk::QueueFamilyProperties[queue_family_count]);
        gpu.getQueueFamilyProperties(&queue_family_count, queue_props.get());

        // Query fine-grained feature support for this device.
        //  If app has specific feature requirements it should check supported
        //  features based on this query
        vk::PhysicalDeviceFeatures physDevFeatures;
        gpu.getFeatures(&physDevFeatures);
    }

    void init_vk_swapchain()
    {
    // Create a WSI surface for the window:
#if defined(VK_USE_PLATFORM_WIN32_KHR)
        {
            auto const createInfo = vk::Win32SurfaceCreateInfoKHR()
                .setHinstance(connection)
                .setHwnd(window);

            auto result = inst.createWin32SurfaceKHR(&createInfo, nullptr, &surface);
            VERIFY(result == vk::Result::eSuccess);
        }
#elif defined(VK_USE_PLATFORM_WAYLAND_KHR) && !defined(VK_USE_PLATFORM_XCB_KHR)
        {
            auto const createInfo = vk::WaylandSurfaceCreateInfoKHR()
                .setDisplay(display)
                .setSurface(window);

            auto result = inst.createWaylandSurfaceKHR(&createInfo, nullptr, &surface);
            VERIFY(result == vk::Result::eSuccess);
        }
#endif
        if(use_xlib)
        {
#if defined(VK_USE_PLATFORM_XLIB_KHR)
            auto const createInfo = vk::XlibSurfaceCreateInfoKHR()
                .setDpy(display)
                .setWindow(xlib_window);

            auto result = inst.createXlibSurfaceKHR(&createInfo, nullptr, &surface);
            VERIFY(result == vk::Result::eSuccess);
#endif
        }
        else
        {
#if defined(VK_USE_PLATFORM_XCB_KHR)
            auto const createInfo = vk::XcbSurfaceCreateInfoKHR()
                .setConnection(connection)
                .setWindow(xcb_window);

            auto result = inst.createXcbSurfaceKHR(&createInfo, nullptr, &surface);
            VERIFY(result == vk::Result::eSuccess);
#endif
        }

        // Iterate over each queue to learn whether it supports presenting:
        std::unique_ptr<vk::Bool32[]> supportsPresent(new vk::Bool32[queue_family_count]);
        for(uint32_t i = 0; i < queue_family_count; i++)
        {
            gpu.getSurfaceSupportKHR(i, surface, &supportsPresent[i]);
        }

        uint32_t graphicsQueueFamilyIndex = UINT32_MAX;
        uint32_t presentQueueFamilyIndex = UINT32_MAX;
        for(uint32_t i = 0; i < queue_family_count; i++)
        {
            if(queue_props[i].queueFlags & vk::QueueFlagBits::eGraphics)
            {
                if(graphicsQueueFamilyIndex == UINT32_MAX)
                {
                    graphicsQueueFamilyIndex = i;
                }

                if (supportsPresent[i] == VK_TRUE)
                {
                    graphicsQueueFamilyIndex = i;
                    presentQueueFamilyIndex = i;
                    break;
                }
            }
        }

        if(presentQueueFamilyIndex == UINT32_MAX)
        {
            // If didn't find a queue that supports both graphics and present, then
            // find a separate present queue.
            for(uint32_t i = 0; i < queue_family_count; ++i)
            {
                if(supportsPresent[i] == VK_TRUE)
                {
                    presentQueueFamilyIndex = i;
                    break;
                }
            }
        }

        // Generate error if could not find both a graphics and a present queue
        if(graphicsQueueFamilyIndex == UINT32_MAX || presentQueueFamilyIndex == UINT32_MAX)
        {
            ERR_EXIT("Could not find both graphics and present queues\n", "Swapchain Initialization Failure");
        }

        graphics_queue_family_index = graphicsQueueFamilyIndex;
        present_queue_family_index = presentQueueFamilyIndex;
        separate_present_queue = (graphics_queue_family_index != present_queue_family_index);

        create_device();

        device.getQueue(graphics_queue_family_index, 0, &graphics_queue);
        if(!separate_present_queue)
        {
            present_queue = graphics_queue;
        }
        else
        {
            device.getQueue(present_queue_family_index, 0, &present_queue);
        }

        // Get the list of VkFormat's that are supported:
        uint32_t formatCount;
        auto result = gpu.getSurfaceFormatsKHR(surface, &formatCount, nullptr);
        VERIFY(result == vk::Result::eSuccess);

        std::unique_ptr<vk::SurfaceFormatKHR[]> surfFormats(new vk::SurfaceFormatKHR[formatCount]);
        result = gpu.getSurfaceFormatsKHR(surface, &formatCount, surfFormats.get());
        VERIFY(result == vk::Result::eSuccess);

        // If the format list includes just one entry of VK_FORMAT_UNDEFINED,
        // the surface has no preferred format.  Otherwise, at least one
        // supported format will be returned.
        if(formatCount == 1 && surfFormats[0].format == vk::Format::eUndefined)
        {
            format = vk::Format::eB8G8R8A8Unorm;
        }
        else
        {
            assert(formatCount >= 1);
            format = surfFormats[0].format;
        }
        color_space = surfFormats[0].colorSpace;

        quit = false;
        curFrame = 0;

        // Create semaphores to synchronize acquiring presentable buffers before
        // rendering and waiting for drawing to be complete before presenting
        auto const semaphoreCreateInfo = vk::SemaphoreCreateInfo();

        // Create fences that we can use to throttle if we get too far
        // ahead of the image presents
        vk::FenceCreateInfo const fence_ci;
        for(uint32_t i = 0; i < FRAME_LAG; i++)
        {
            device.createFence(&fence_ci, nullptr, &fences[i]);
            fencesInited[i] = false;
            result = device.createSemaphore(&semaphoreCreateInfo, nullptr, &image_acquired_semaphores[i]);
            VERIFY(result == vk::Result::eSuccess);

            result = device.createSemaphore(&semaphoreCreateInfo, nullptr, &draw_complete_semaphores[i]);
            VERIFY(result == vk::Result::eSuccess);

            if(separate_present_queue)
            {
                result = device.createSemaphore(&semaphoreCreateInfo, nullptr, &image_ownership_semaphores[i]);
                VERIFY(result == vk::Result::eSuccess);
            }
        }
        frame_index = 0;

        // Get Memory information and properties
        gpu.getMemoryProperties(&memory_properties);
    }

    void prepare()
    {
        auto const cmd_pool_info = vk::CommandPoolCreateInfo()
            .setQueueFamilyIndex(graphics_queue_family_index);
        auto result = device.createCommandPool(&cmd_pool_info, nullptr, &cmd_pool);
        VERIFY(result == vk::Result::eSuccess);

        auto const cmd = vk::CommandBufferAllocateInfo()
            .setCommandPool(cmd_pool)
            .setLevel(vk::CommandBufferLevel::ePrimary)
            .setCommandBufferCount(1);

        prepare_buffers();
        prepare_depth();
        prepare_textures();
        prepare_cube_data_buffer();

        prepare_descriptor_layout();
        prepare_render_pass();
        prepare_pipeline();

        for(uint32_t i = 0; i < swapchainImageCount; ++i)
        {
            result = device.allocateCommandBuffers(&cmd, &buffers[i].cmd);
            VERIFY(result == vk::Result::eSuccess);
        }

        if(separate_present_queue)
        {
            auto const cmd_pool_info = vk::CommandPoolCreateInfo()
                .setQueueFamilyIndex(present_queue_family_index);

            result = device.createCommandPool(&cmd_pool_info, nullptr, &present_cmd_pool);
            VERIFY(result == vk::Result::eSuccess);

            auto const cmd = vk::CommandBufferAllocateInfo()
                .setCommandPool(present_cmd_pool)
                .setLevel(vk::CommandBufferLevel::ePrimary)
                .setCommandBufferCount(1);

            for(uint32_t i = 0; i < swapchainImageCount; i++)
            {
                result = device.allocateCommandBuffers(&cmd, &buffers[i].graphics_to_present_cmd);
                VERIFY(result == vk::Result::eSuccess);

                build_image_ownership_cmd(i);
            }
        }

        prepare_descriptor_pool();
        prepare_descriptor_set();

        prepare_framebuffers();

        for(uint32_t i = 0; i < swapchainImageCount; ++i)
        {
            current_buffer = i;
            draw_build_cmd(buffers[i].cmd);
        }

        /*
         * Prepare functions above may generate pipeline commands
         * that need to be flushed before beginning the render loop.
         */
        flush_init_cmd();

        current_buffer = 0;
        prepared = true;
    }

    void prepare_buffers()
    {
        vk::SwapchainKHR oldSwapchain = swapchain;

        // Check the surface capabilities and formats
        vk::SurfaceCapabilitiesKHR surfCapabilities;
        auto result = gpu.getSurfaceCapabilitiesKHR(surface, &surfCapabilities);
        VERIFY(result == vk::Result::eSuccess);

        uint32_t presentModeCount;
        result = gpu.getSurfacePresentModesKHR(surface, &presentModeCount, nullptr);
        VERIFY(result == vk::Result::eSuccess);

        std::unique_ptr<vk::PresentModeKHR[]> presentModes(new vk::PresentModeKHR[presentModeCount]);
        result = gpu.getSurfacePresentModesKHR(surface, &presentModeCount, presentModes.get());
        VERIFY(result == vk::Result::eSuccess);

        vk::Extent2D swapchainExtent;
        // width and height are either both -1, or both not -1.
        if(surfCapabilities.currentExtent.width == (uint32_t)-1)
        {
            // If the surface size is undefined, the size is set to
            // the size of the images requested.
            swapchainExtent.width = width;
            swapchainExtent.height = height;
        }
        else
        {
            // If the surface size is defined, the swap chain size must match
            swapchainExtent = surfCapabilities.currentExtent;
            width = surfCapabilities.currentExtent.width;
            height = surfCapabilities.currentExtent.height;
        }

        // The FIFO present mode is guaranteed by the spec to be supported
        // and to have no tearing.  It's a great default present mode to use.
        vk::PresentModeKHR swapchainPresentMode = vk::PresentModeKHR::eFifo;

        //  There are times when you may wish to use another present mode.  The
        //  following code shows how to select them, and the comments provide some
        //  reasons you may wish to use them.
        //
        // It should be noted that Vulkan 1.0 doesn't provide a method for
        // synchronizing rendering with the presentation engine's display.  There
        // is a method provided for throttling rendering with the display, but
        // there are some presentation engines for which this method will not work.
        // If an application doesn't throttle its rendering, and if it renders much
        // faster than the refresh rate of the display, this can waste power on
        // mobile devices.  That is because power is being spent rendering images
        // that may never be seen.
//#define DESIRE_VK_PRESENT_MODE_IMMEDIATE_KHR
//#define DESIRE_VK_PRESENT_MODE_MAILBOX_KHR
//#define DESIRE_VK_PRESENT_MODE_FIFO_RELAXED_KHR
#if defined(DESIRE_VK_PRESENT_MODE_IMMEDIATE_KHR)
        // VK_PRESENT_MODE_IMMEDIATE_KHR is for applications that don't care about
        // tearing, or have some way of synchronizing their rendering with the
        // display.
        for(size_t i = 0; i < presentModeCount; ++i)
        {
            if(presentModes[i] == vk::PresentModeKHR::eImmediate)
            {
                swapchainPresentMode = vk::PresentModeKHR::eImmediate;
                break;
            }
        }
#elif defined(DESIRE_VK_PRESENT_MODE_MAILBOX_KHR)
        // VK_PRESENT_MODE_MAILBOX_KHR may be useful for applications that
        // generally render a new presentable image every refresh cycle, but are
        // occasionally early.  In this case, the application wants the new image
        // to be displayed instead of the previously-queued-for-presentation image
        // that has not yet been displayed.
        for(size_t i = 0; i < presentModeCount; ++i)
        {
            if (presentModes[i] == vk::PresentModeKHR::eMailbox)
            {
                swapchainPresentMode = vk::PresentModeKHR::eMailbox;
                break;
            }
        }
#elif defined(DESIRE_VK_PRESENT_MODE_FIFO_RELAXED_KHR)
        // VK_PRESENT_MODE_FIFO_RELAXED_KHR is for applications that generally
        // render a new presentable image every refresh cycle, but are occasionally
        // late.  In this case (perhaps because of stuttering/latency concerns),
        // the application wants the late image to be immediately displayed, even
        // though that may mean some tearing.
        for(size_t i = 0; i < presentModeCount; ++i)
        {
            if(presentModes[i] == vk::PresentModeKHR::eFifoRelaxed)
            {
                swapchainPresentMode = vk::PresentModeKHR::eFifoRelaxed;
                break;
            }
        }
#endif

        // Determine the number of VkImage's to use in the swap chain (we desire to
        // own only 1 image at a time, besides the images being displayed and
        // queued for display):
        uint32_t desiredNumberOfSwapchainImages = surfCapabilities.minImageCount + 1;
        // If maxImageCount is 0, we can ask for as many images as we want, otherwise
        // we're limited to maxImageCount
        if((surfCapabilities.maxImageCount > 0) && (desiredNumberOfSwapchainImages > surfCapabilities.maxImageCount))
        {
            // Application must settle for fewer images than desired:
            desiredNumberOfSwapchainImages = surfCapabilities.maxImageCount;
        }

        vk::SurfaceTransformFlagBitsKHR preTransform;
        if(surfCapabilities.supportedTransforms & vk::SurfaceTransformFlagBitsKHR::eIdentity)
        {
            preTransform = vk::SurfaceTransformFlagBitsKHR::eIdentity;
        }
        else
        {
            preTransform = surfCapabilities.currentTransform;
        }

        auto const swapchain_ci = vk::SwapchainCreateInfoKHR()
            .setSurface(surface)
            .setMinImageCount(desiredNumberOfSwapchainImages)
            .setImageFormat(format)
            .setImageColorSpace(color_space)
            .setImageExtent({ swapchainExtent.width, swapchainExtent.height })
            .setImageArrayLayers(1)
            .setImageUsage(vk::ImageUsageFlagBits::eColorAttachment)
            .setImageSharingMode(vk::SharingMode::eExclusive)
            .setQueueFamilyIndexCount(0)
            .setPQueueFamilyIndices(nullptr)
            .setPreTransform(preTransform)
            .setCompositeAlpha(vk::CompositeAlphaFlagBitsKHR::eOpaque)
            .setPresentMode(swapchainPresentMode)
            .setClipped(true)
            .setOldSwapchain(oldSwapchain);

        result = device.createSwapchainKHR(&swapchain_ci, nullptr, &swapchain);
        VERIFY(result == vk::Result::eSuccess);

        // If we just re-created an existing swapchain, we should destroy the old
        // swapchain at this point.
        // Note: destroying the swapchain also cleans up all its associated
        // presentable images once the platform is done with them.
        if(oldSwapchain)
        {
            device.destroySwapchainKHR(oldSwapchain, nullptr);
        }

        result = device.getSwapchainImagesKHR(swapchain, &swapchainImageCount, nullptr);
        VERIFY(result == vk::Result::eSuccess);

        std::unique_ptr<vk::Image[]> swapchainImages(new vk::Image[swapchainImageCount]);
        result = device.getSwapchainImagesKHR(swapchain, &swapchainImageCount, swapchainImages.get());
        VERIFY(result == vk::Result::eSuccess);

        buffers.reset(new SwapchainBuffers[swapchainImageCount]);

        for(uint32_t i = 0; i < swapchainImageCount; ++i)
        {
            auto const color_image_view = vk::ImageViewCreateInfo()
                .setImage(swapchainImages[i])
                .setViewType(vk::ImageViewType::e2D)
                .setFormat(format)
                .setSubresourceRange(vk::ImageSubresourceRange(vk::ImageAspectFlagBits::eColor, 0, 1, 0, 1));

            buffers[i].image = swapchainImages[i];

            result = device.createImageView(&color_image_view, nullptr, &buffers[i].view);
            VERIFY(result == vk::Result::eSuccess);

            // The draw loop will be expecting the presentable images to be in
            // LAYOUT_PRESENT_SRC_KHR since that's how they're left at the end of every frame.
            set_image_layout(buffers[i].image, vk::ImageAspectFlagBits::eColor, vk::ImageLayout::eUndefined,
                vk::ImageLayout::ePresentSrcKHR, vk::AccessFlagBits());
        }
    }

    void prepare_cube_data_buffer()
    {
        mat4x4 VP;
        mat4x4_mul(VP, projection_matrix, view_matrix);

        mat4x4 MVP;
        mat4x4_mul(MVP, VP, model_matrix);

        vktexcube_vs_uniform data;
        memcpy(data.mvp, MVP, sizeof(MVP));
        //    dumpMatrix("MVP", MVP)
        for(int32_t i = 0; i < 12 * 3; i++)
        {
            data.position[i][0] = g_vertex_buffer_data[i * 3];
            data.position[i][1] = g_vertex_buffer_data[i * 3 + 1];
            data.position[i][2] = g_vertex_buffer_data[i * 3 + 2];
            data.position[i][3] = 1.0f;
            data.attr[i][0] = g_uv_buffer_data[2 * i];
            data.attr[i][1] = g_uv_buffer_data[2 * i + 1];
            data.attr[i][2] = 0;
            data.attr[i][3] = 0;
        }

        auto const buf_info = vk::BufferCreateInfo()
            .setSize(sizeof(data))
            .setUsage(vk::BufferUsageFlagBits::eUniformBuffer);
        auto result = device.createBuffer(&buf_info, nullptr, &uniform_data.buf);
        VERIFY(result == vk::Result::eSuccess);

        vk::MemoryRequirements mem_reqs;
        device.getBufferMemoryRequirements(uniform_data.buf, &mem_reqs);

        uniform_data.mem_alloc.setAllocationSize(mem_reqs.size);
        uniform_data.mem_alloc.setMemoryTypeIndex(0);

        bool const pass = memory_type_from_properties(mem_reqs.memoryTypeBits,
            vk::MemoryPropertyFlagBits::eHostVisible | vk::MemoryPropertyFlagBits::eHostCoherent,
            &uniform_data.mem_alloc.memoryTypeIndex);
        VERIFY(pass);

        result = device.allocateMemory(&uniform_data.mem_alloc, nullptr, &(uniform_data.mem));
        VERIFY(result == vk::Result::eSuccess);

        auto pData = device.mapMemory(uniform_data.mem, 0, uniform_data.mem_alloc.allocationSize, vk::MemoryMapFlags());
        VERIFY(pData.result == vk::Result::eSuccess);

        memcpy(pData.value, &data, sizeof data);

        device.unmapMemory(uniform_data.mem);

        result = device.bindBufferMemory(uniform_data.buf, uniform_data.mem, 0);
        VERIFY(result == vk::Result::eSuccess);

        uniform_data.buffer_info.buffer = uniform_data.buf;
        uniform_data.buffer_info.offset = 0;
        uniform_data.buffer_info.range = sizeof(data);
    }

    void prepare_depth()
    {
        depth.format = vk::Format::eD16Unorm;

        auto const image = vk::ImageCreateInfo()
            .setImageType(vk::ImageType::e2D)
            .setFormat(depth.format)
            .setExtent({(uint32_t)width, (uint32_t)height, 1})
            .setMipLevels(1)
            .setArrayLayers(1)
            .setSamples(vk::SampleCountFlagBits::e1)
            .setTiling(vk::ImageTiling::eOptimal)
            .setUsage(vk::ImageUsageFlagBits::eDepthStencilAttachment)
            .setSharingMode(vk::SharingMode::eExclusive)
            .setQueueFamilyIndexCount(0)
            .setPQueueFamilyIndices(nullptr)
            .setInitialLayout(vk::ImageLayout::eUndefined);

        auto result = device.createImage(&image, nullptr, &depth.image);
        VERIFY(result == vk::Result::eSuccess);

        vk::MemoryRequirements mem_reqs;
        device.getImageMemoryRequirements(depth.image, &mem_reqs);

        depth.mem_alloc.setAllocationSize(mem_reqs.size);
        depth.mem_alloc.setMemoryTypeIndex(0);

        auto const pass = memory_type_from_properties(mem_reqs.memoryTypeBits, vk::MemoryPropertyFlagBits(0),
            &depth.mem_alloc.memoryTypeIndex);
        VERIFY(pass);

        result = device.allocateMemory(&depth.mem_alloc, nullptr, &depth.mem);
        VERIFY(result == vk::Result::eSuccess);

        result = device.bindImageMemory(depth.image, depth.mem, 0);
        VERIFY(result == vk::Result::eSuccess);

        set_image_layout(depth.image, vk::ImageAspectFlagBits::eDepth, vk::ImageLayout::eUndefined,
            vk::ImageLayout::eDepthStencilAttachmentOptimal, vk::AccessFlagBits());

        auto const view = vk::ImageViewCreateInfo()
            .setImage(depth.image)
            .setViewType(vk::ImageViewType::e2D)
            .setFormat(depth.format)
            .setSubresourceRange(vk::ImageSubresourceRange(vk::ImageAspectFlagBits::eDepth, 0, 1, 0, 1));
        result = device.createImageView(&view, nullptr, &depth.view);
        VERIFY(result == vk::Result::eSuccess);
    }

    void prepare_descriptor_layout()
    {
        vk::DescriptorSetLayoutBinding const layout_bindings[2] =
        {
            vk::DescriptorSetLayoutBinding()
                .setBinding(0)
                .setDescriptorType(vk::DescriptorType::eUniformBuffer)
                .setDescriptorCount(1)
                .setStageFlags(vk::ShaderStageFlagBits::eVertex)
                .setPImmutableSamplers(nullptr),
            vk::DescriptorSetLayoutBinding()
                .setBinding(1)
                .setDescriptorType(vk::DescriptorType::eCombinedImageSampler)
                .setDescriptorCount(texture_count)
                .setStageFlags(vk::ShaderStageFlagBits::eFragment)
                .setPImmutableSamplers(nullptr)
        };

        auto const descriptor_layout = vk::DescriptorSetLayoutCreateInfo()
            .setBindingCount(2)
            .setPBindings(layout_bindings);

        auto result = device.createDescriptorSetLayout(&descriptor_layout, nullptr, &desc_layout);
        VERIFY(result == vk::Result::eSuccess);

        auto const pPipelineLayoutCreateInfo = vk::PipelineLayoutCreateInfo()
            .setSetLayoutCount(1)
            .setPSetLayouts(&desc_layout);

        result = device.createPipelineLayout(&pPipelineLayoutCreateInfo, nullptr, &pipeline_layout);
        VERIFY(result == vk::Result::eSuccess);
    }

    void prepare_descriptor_pool()
    {
        vk::DescriptorPoolSize const poolSizes[2] =
        {
            vk::DescriptorPoolSize()
                .setType(vk::DescriptorType::eUniformBuffer)
                .setDescriptorCount(1),
            vk::DescriptorPoolSize()
                .setType(vk::DescriptorType::eCombinedImageSampler)
                .setDescriptorCount(texture_count)
        };

        auto const descriptor_pool = vk::DescriptorPoolCreateInfo()
            .setMaxSets(1)
            .setPoolSizeCount(2)
            .setPPoolSizes(poolSizes);

        auto result = device.createDescriptorPool(&descriptor_pool, nullptr, &desc_pool);
        VERIFY(result == vk::Result::eSuccess);
    }

    void prepare_descriptor_set()
    {
        auto const alloc_info = vk::DescriptorSetAllocateInfo()
            .setDescriptorPool(desc_pool)
            .setDescriptorSetCount(1)
            .setPSetLayouts(&desc_layout);
        auto result = device.allocateDescriptorSets(&alloc_info, &desc_set);
        VERIFY(result == vk::Result::eSuccess);

        vk::DescriptorImageInfo tex_descs[texture_count];
        for(uint32_t i = 0; i < texture_count; i++)
        {
            tex_descs[i].setSampler(textures[i].sampler);
            tex_descs[i].setImageView(textures[i].view);
            tex_descs[i].setImageLayout(vk::ImageLayout::eGeneral);
        }

        vk::WriteDescriptorSet writes[2];

        writes[0].setDstSet(desc_set);
        writes[0].setDescriptorCount(1);
        writes[0].setDescriptorType(vk::DescriptorType::eUniformBuffer);
        writes[0].setPBufferInfo(&uniform_data.buffer_info);

        writes[1].setDstSet(desc_set);
        writes[1].setDstBinding(1);
        writes[1].setDescriptorCount(texture_count);
        writes[1].setDescriptorType(vk::DescriptorType::eCombinedImageSampler);
        writes[1].setPImageInfo(tex_descs);

        device.updateDescriptorSets(2, writes, 0, nullptr);
    }

    void prepare_framebuffers()
    {
        vk::ImageView attachments[2];
        attachments[1] = depth.view;

        auto const fb_info = vk::FramebufferCreateInfo()
            .setRenderPass(render_pass)
            .setAttachmentCount(2)
            .setPAttachments(attachments)
            .setWidth((uint32_t)width)
            .setHeight((uint32_t)height)
            .setLayers(1);

        framebuffers.reset(new vk::Framebuffer[swapchainImageCount]);

        for(uint32_t i = 0; i < swapchainImageCount; i++)
        {
            attachments[0] = buffers[i].view;
            auto const result = device.createFramebuffer(&fb_info, nullptr, &framebuffers[i]);
            VERIFY(result == vk::Result::eSuccess);
        }
    }

    vk::ShaderModule prepare_fs()
    {
        size_t size;
        void *fragShaderCode = read_spv("cube-frag.spv", &size);

        frag_shader_module = prepare_shader_module(fragShaderCode, size);

        free(fragShaderCode);

        return frag_shader_module;
    }

    void prepare_pipeline()
    {
        vk::PipelineCacheCreateInfo const pipelineCacheInfo;
        auto result = device.createPipelineCache(&pipelineCacheInfo, nullptr, &pipelineCache);
        VERIFY(result == vk::Result::eSuccess);

        vk::PipelineShaderStageCreateInfo const shaderStageInfo[2] =
        {
            vk::PipelineShaderStageCreateInfo()
                .setStage(vk::ShaderStageFlagBits::eVertex)
                .setModule(prepare_vs())
                .setPName("main"),
            vk::PipelineShaderStageCreateInfo()
                .setStage(vk::ShaderStageFlagBits::eFragment)
                .setModule(prepare_fs())
                .setPName("main")
        };

        vk::PipelineVertexInputStateCreateInfo const vertexInputInfo;

        auto const inputAssemblyInfo = vk::PipelineInputAssemblyStateCreateInfo()
            .setTopology(vk::PrimitiveTopology::eTriangleList);

        // TODO: Where are pViewports and pScissors set?
        auto const viewportInfo = vk::PipelineViewportStateCreateInfo()
            .setViewportCount(1)
            .setScissorCount(1);

        auto const rasterizationInfo = vk::PipelineRasterizationStateCreateInfo()
            .setDepthClampEnable(VK_FALSE)
            .setRasterizerDiscardEnable(VK_FALSE)
            .setPolygonMode(vk::PolygonMode::eFill)
            .setCullMode(vk::CullModeFlagBits::eBack)
            .setFrontFace(vk::FrontFace::eCounterClockwise)
            .setDepthBiasEnable(VK_FALSE)
            .setLineWidth(1.0f);

        auto const multisampleInfo = vk::PipelineMultisampleStateCreateInfo();

        auto const stencilOp = vk::StencilOpState()
            .setFailOp(vk::StencilOp::eKeep)
            .setPassOp(vk::StencilOp::eKeep)
            .setCompareOp(vk::CompareOp::eAlways);

        auto const depthStencilInfo = vk::PipelineDepthStencilStateCreateInfo()
            .setDepthTestEnable(VK_TRUE)
            .setDepthWriteEnable(VK_TRUE)
            .setDepthCompareOp(vk::CompareOp::eLessOrEqual)
            .setDepthBoundsTestEnable(VK_FALSE)
            .setStencilTestEnable(VK_FALSE)
            .setFront(stencilOp)
            .setBack(stencilOp);

        vk::PipelineColorBlendAttachmentState const colorBlendAttachments[1] =
        {
            vk::PipelineColorBlendAttachmentState()
                .setColorWriteMask(vk::ColorComponentFlagBits::eR| vk::ColorComponentFlagBits::eG | vk::ColorComponentFlagBits::eB
                    | vk::ColorComponentFlagBits::eA)
        };

        auto const colorBlendInfo = vk::PipelineColorBlendStateCreateInfo()
            .setAttachmentCount(1)
            .setPAttachments(colorBlendAttachments);

        vk::DynamicState const dynamicStates[2] =
        {
            vk::DynamicState::eViewport,
            vk::DynamicState::eScissor
        };

        auto const dynamicStateInfo = vk::PipelineDynamicStateCreateInfo()
            .setPDynamicStates(dynamicStates)
            .setDynamicStateCount(2);

        auto const pipeline = vk::GraphicsPipelineCreateInfo()
            .setStageCount(2)
            .setPStages(shaderStageInfo)
            .setPVertexInputState(&vertexInputInfo)
            .setPInputAssemblyState(&inputAssemblyInfo)
            .setPViewportState(&viewportInfo)
            .setPRasterizationState(&rasterizationInfo)
            .setPMultisampleState(&multisampleInfo)
            .setPDepthStencilState(&depthStencilInfo)
            .setPColorBlendState(&colorBlendInfo)
            .setPDynamicState(&dynamicStateInfo)
            .setLayout(pipeline_layout)
            .setRenderPass(render_pass);

        result = device.createGraphicsPipelines(pipelineCache, 1, &pipeline, nullptr, &this->pipeline);
        VERIFY(result == vk::Result::eSuccess);

        device.destroyShaderModule(frag_shader_module, nullptr);
        device.destroyShaderModule(vert_shader_module, nullptr);
    }

    void prepare_render_pass()
    {
        const vk::AttachmentDescription attachments[2] =
        {
            vk::AttachmentDescription()
                .setFlags(vk::AttachmentDescriptionFlagBits::eMayAlias)
                .setFormat(format)
                .setSamples(vk::SampleCountFlagBits::e1)
                .setLoadOp(vk::AttachmentLoadOp::eClear)
                .setStoreOp(vk::AttachmentStoreOp::eStore)
                .setStencilLoadOp(vk::AttachmentLoadOp::eDontCare)
                .setStencilStoreOp(vk::AttachmentStoreOp::eDontCare)
                .setInitialLayout(vk::ImageLayout::eColorAttachmentOptimal)
                .setFinalLayout(vk::ImageLayout::ePresentSrcKHR),
            vk::AttachmentDescription()
                .setFlags(vk::AttachmentDescriptionFlagBits::eMayAlias)
                .setFormat(depth.format)
                .setSamples(vk::SampleCountFlagBits::e1)
                .setLoadOp(vk::AttachmentLoadOp::eClear)
                .setStoreOp(vk::AttachmentStoreOp::eDontCare)
                .setStencilLoadOp(vk::AttachmentLoadOp::eDontCare)
                .setStencilStoreOp(vk::AttachmentStoreOp::eDontCare)
                .setInitialLayout(vk::ImageLayout::eDepthStencilAttachmentOptimal)
                .setFinalLayout(vk::ImageLayout::eDepthStencilAttachmentOptimal)
        };

        auto const color_reference = vk::AttachmentReference()
            .setAttachment(0)
            .setLayout(vk::ImageLayout::eColorAttachmentOptimal);

        auto const depth_reference = vk::AttachmentReference()
            .setAttachment(1)
            .setLayout(vk::ImageLayout::eDepthStencilAttachmentOptimal);

        auto const subpass = vk::SubpassDescription()
            .setPipelineBindPoint(vk::PipelineBindPoint::eGraphics)
            .setInputAttachmentCount(0)
            .setPInputAttachments(nullptr)
            .setColorAttachmentCount(1)
            .setPColorAttachments(&color_reference)
            .setPResolveAttachments(nullptr)
            .setPDepthStencilAttachment(&depth_reference)
            .setPreserveAttachmentCount(0)
            .setPPreserveAttachments(nullptr);

        auto const rp_info = vk::RenderPassCreateInfo()
            .setAttachmentCount(2)
            .setPAttachments(attachments)
            .setSubpassCount(1)
            .setPSubpasses(&subpass)
            .setDependencyCount(0)
            .setPDependencies(nullptr);

        auto result = device.createRenderPass(&rp_info, nullptr, &render_pass);
        VERIFY(result == vk::Result::eSuccess);
    }

    vk::ShaderModule prepare_shader_module(const void *code, size_t size)
    {
        auto const moduleCreateInfo = vk::ShaderModuleCreateInfo()
            .setCodeSize(size)
            .setPCode((uint32_t const*)code);

        vk::ShaderModule module;
        auto result = device.createShaderModule(&moduleCreateInfo, nullptr, &module);
        VERIFY(result == vk::Result::eSuccess);

        return module;
    }

    void prepare_texture_image(const char *filename, texture_object *tex_obj, vk::ImageTiling tiling,
        vk::ImageUsageFlags usage, vk::MemoryPropertyFlags required_props)
    {
        int32_t tex_width;
        int32_t tex_height;
        if(!loadTexture(filename, nullptr, nullptr, &tex_width, &tex_height))
        {
            ERR_EXIT("Failed to load textures", "Load Texture Failure");
        }

        tex_obj->tex_width = tex_width;
        tex_obj->tex_height = tex_height;

        auto const image_create_info = vk::ImageCreateInfo()
            .setImageType(vk::ImageType::e2D)
            .setFormat(vk::Format::eR8G8B8A8Unorm)
            .setExtent({(uint32_t)tex_width, (uint32_t)tex_height, 1})
            .setMipLevels(1)
            .setArrayLayers(1)
            .setSamples(vk::SampleCountFlagBits::e1)
            .setTiling(tiling)
            .setUsage(usage)
            .setSharingMode(vk::SharingMode::eExclusive)
            .setQueueFamilyIndexCount(0)
            .setPQueueFamilyIndices(nullptr)
            .setInitialLayout(vk::ImageLayout::ePreinitialized);

        auto result = device.createImage(&image_create_info, nullptr, &tex_obj->image);
        VERIFY(result == vk::Result::eSuccess);

        vk::MemoryRequirements mem_reqs;
        device.getImageMemoryRequirements(tex_obj->image, &mem_reqs);

        tex_obj->mem_alloc.setAllocationSize(mem_reqs.size);
        tex_obj->mem_alloc.setMemoryTypeIndex(0);

        auto pass = memory_type_from_properties(mem_reqs.memoryTypeBits, required_props, &tex_obj->mem_alloc.memoryTypeIndex);
        VERIFY(pass == true);

        result = device.allocateMemory(&tex_obj->mem_alloc, nullptr, &(tex_obj->mem));
        VERIFY(result == vk::Result::eSuccess);

        result = device.bindImageMemory(tex_obj->image, tex_obj->mem, 0);
        VERIFY(result == vk::Result::eSuccess);

        if(required_props & vk::MemoryPropertyFlagBits::eHostVisible)
        {
            auto const subres = vk::ImageSubresource()
                .setAspectMask(vk::ImageAspectFlagBits::eColor)
                .setMipLevel(0)
                .setArrayLayer(0);
            vk::SubresourceLayout layout;
            device.getImageSubresourceLayout(tex_obj->image, &subres, &layout);

            auto data = device.mapMemory(tex_obj->mem, 0, tex_obj->mem_alloc.allocationSize);
            VERIFY(data.result == vk::Result::eSuccess);

            if(!loadTexture(filename, (uint8_t*)data.value, &layout, &tex_width, &tex_height))
            {
                fprintf(stderr, "Error loading texture: %s\n", filename);
            }

            device.unmapMemory(tex_obj->mem);
        }

        tex_obj->imageLayout = vk::ImageLayout::eShaderReadOnlyOptimal;
        set_image_layout(tex_obj->image, vk::ImageAspectFlagBits::eColor, vk::ImageLayout::ePreinitialized, tex_obj->imageLayout,
            vk::AccessFlagBits::eHostWrite);
    }

    void prepare_textures()
    {
        vk::Format const tex_format = vk::Format::eR8G8B8A8Unorm;
        vk::FormatProperties props;
        gpu.getFormatProperties(tex_format, &props);

        for(uint32_t i = 0; i < texture_count; i++)
        {
            if((props.linearTilingFeatures & vk::FormatFeatureFlagBits::eSampledImage) && !use_staging_buffer)
            {
                /* Device can texture using linear textures */
                prepare_texture_image(tex_files[i], &textures[i], vk::ImageTiling::eLinear,
                    vk::ImageUsageFlagBits::eSampled,
                    vk::MemoryPropertyFlagBits::eHostVisible | vk::MemoryPropertyFlagBits::eHostCoherent);
            }
            else if(props.optimalTilingFeatures & vk::FormatFeatureFlagBits::eSampledImage)
            {
                /* Must use staging buffer to copy linear texture to optimized */
                texture_object staging_texture;

                prepare_texture_image(tex_files[i], &staging_texture, vk::ImageTiling::eLinear,
                    vk::ImageUsageFlagBits::eTransferSrc,
                    vk::MemoryPropertyFlagBits::eHostVisible | vk::MemoryPropertyFlagBits::eHostCoherent);

                prepare_texture_image(tex_files[i], &textures[i], vk::ImageTiling::eOptimal,
                    vk::ImageUsageFlagBits::eTransferDst | vk::ImageUsageFlagBits::eSampled,
                    vk::MemoryPropertyFlagBits::eDeviceLocal);

                set_image_layout(staging_texture.image, vk::ImageAspectFlagBits::eColor, staging_texture.imageLayout,
                    vk::ImageLayout::eTransferSrcOptimal, vk::AccessFlags());

                set_image_layout(textures[i].image, vk::ImageAspectFlagBits::eColor, textures[i].imageLayout,
                    vk::ImageLayout::eTransferDstOptimal, vk::AccessFlags());

                auto const subresource = vk::ImageSubresourceLayers()
                    .setAspectMask(vk::ImageAspectFlagBits::eColor)
                    .setMipLevel(0)
                    .setBaseArrayLayer(0)
                    .setLayerCount(1);

                auto const copy_region = vk::ImageCopy()
                    .setSrcSubresource(subresource)
                    .setSrcOffset({0, 0, 0})
                    .setDstSubresource(subresource)
                    .setDstOffset({0, 0, 0})
                    .setExtent({(uint32_t)staging_texture.tex_width, (uint32_t)staging_texture.tex_height, 1});

                cmd.copyImage(staging_texture.image, vk::ImageLayout::eTransferSrcOptimal, textures[i].image,
                    vk::ImageLayout::eTransferDstOptimal, 1, &copy_region);

                set_image_layout(textures[i].image, vk::ImageAspectFlagBits::eColor, vk::ImageLayout::eTransferDstOptimal,
                    textures[i].imageLayout, vk::AccessFlags());

                flush_init_cmd();

                destroy_texture_image(&staging_texture);
            }
            else
            {
                assert(!"No support for R8G8B8A8_UNORM as texture image format");
            }

            auto const samplerInfo = vk::SamplerCreateInfo()
                .setMagFilter(vk::Filter::eNearest)
                .setMinFilter(vk::Filter::eNearest)
                .setMipmapMode(vk::SamplerMipmapMode::eNearest)
                .setAddressModeU(vk::SamplerAddressMode::eClampToEdge)
                .setAddressModeV(vk::SamplerAddressMode::eClampToEdge)
                .setAddressModeW(vk::SamplerAddressMode::eClampToEdge)
                .setMipLodBias(0.0f)
                .setAnisotropyEnable(VK_FALSE)
                .setMaxAnisotropy(1)
                .setCompareEnable(VK_FALSE)
                .setCompareOp(vk::CompareOp::eNever)
                .setMinLod(0.0f)
                .setMaxLod(0.0f)
                .setBorderColor(vk::BorderColor::eFloatOpaqueWhite)
                .setUnnormalizedCoordinates(VK_FALSE);

            auto result = device.createSampler(&samplerInfo, nullptr, &textures[i].sampler);
            VERIFY(result == vk::Result::eSuccess);

            auto const viewInfo = vk::ImageViewCreateInfo()
                .setImage(textures[i].image)
                .setViewType(vk::ImageViewType::e2D)
                .setFormat(tex_format)
                .setSubresourceRange(vk::ImageSubresourceRange(vk::ImageAspectFlagBits::eColor, 0, 1, 0, 1));

            result = device.createImageView(&viewInfo, nullptr, &textures[i].view);
            VERIFY(result == vk::Result::eSuccess);
        }
    }

    vk::ShaderModule prepare_vs()
    {
        size_t size;
        void* vertShaderCode = read_spv("cube-vert.spv", &size);

        vert_shader_module = prepare_shader_module(vertShaderCode, size);

        free(vertShaderCode);

        return vert_shader_module;
    }

    char *read_spv(const char *filename, size_t *psize)
    {
        FILE *fp = fopen(filename, "rb");
        if(!fp)
        {
            return nullptr;
        }

        fseek(fp, 0L, SEEK_END);
        long int size = ftell(fp);

        fseek(fp, 0L, SEEK_SET);

        void *shader_code = malloc(size);
        size_t retval = fread(shader_code, size, 1, fp);
        VERIFY(retval == 1);

        *psize = size;

        fclose(fp);

        return (char*)shader_code;
    }

    void resize()
    {
        uint32_t i;

        // Don't react to resize until after first initialization.
        if(!prepared)
        {
            return;
        }

        // In order to properly resize the window, we must re-create the swapchain
        // AND redo the command buffers, etc.
        //
        // First, perform part of the cleanup() function:
        prepared = false;
        auto result = device.waitIdle();
        VERIFY(result == vk::Result::eSuccess);

        for(i = 0; i < swapchainImageCount; i++)
        {
            device.destroyFramebuffer(framebuffers[i], nullptr);
        }

        device.destroyDescriptorPool(desc_pool, nullptr);

        device.destroyPipeline(pipeline, nullptr);
        device.destroyPipelineCache(pipelineCache, nullptr);
        device.destroyRenderPass(render_pass, nullptr);
        device.destroyPipelineLayout(pipeline_layout, nullptr);
        device.destroyDescriptorSetLayout(desc_layout, nullptr);

        for(i = 0; i < texture_count; i++)
        {
            device.destroyImageView(textures[i].view, nullptr);
            device.destroyImage(textures[i].image, nullptr);
            device.freeMemory(textures[i].mem, nullptr);
            device.destroySampler(textures[i].sampler, nullptr);
        }

        device.destroyImageView(depth.view, nullptr);
        device.destroyImage(depth.image, nullptr);
        device.freeMemory(depth.mem, nullptr);

        device.destroyBuffer(uniform_data.buf, nullptr);
        device.freeMemory(uniform_data.mem, nullptr);

        for(i = 0; i < swapchainImageCount; i++)
        {
            device.destroyImageView(buffers[i].view, nullptr);
            device.freeCommandBuffers(cmd_pool, 1, &buffers[i].cmd);
        }

        device.destroyCommandPool(cmd_pool, nullptr);
        if(separate_present_queue)
        {
            device.destroyCommandPool(present_cmd_pool, nullptr);
        }

        // Second, re-perform the prepare() function, which will re-create the swapchain.
        prepare();
    }

    void set_image_layout(vk::Image image, vk::ImageAspectFlags aspectMask, vk::ImageLayout oldLayout,
        vk::ImageLayout newLayout, vk::AccessFlags srcAccessMask)
    {
        if(!cmd)
        {
            auto const cmd = vk::CommandBufferAllocateInfo()
                .setCommandPool(cmd_pool)
                .setLevel(vk::CommandBufferLevel::ePrimary)
                .setCommandBufferCount(1);

            auto result = device.allocateCommandBuffers(&cmd, &this->cmd);
            VERIFY(result == vk::Result::eSuccess);

            auto const cmd_buf_info = vk::CommandBufferBeginInfo()
                .setPInheritanceInfo(nullptr);

            result = this->cmd.begin(&cmd_buf_info);
            VERIFY(result == vk::Result::eSuccess);
        }

        auto DstAccessMask = [](vk::ImageLayout const& layout)
        {
            vk::AccessFlags flags;

            switch(layout)
            {
                case vk::ImageLayout::eTransferDstOptimal:
                    // Make sure anything that was copying from this image has completed
                    flags = vk::AccessFlagBits::eTransferRead;
                    break;
                case vk::ImageLayout::eColorAttachmentOptimal:
                    flags = vk::AccessFlagBits::eColorAttachmentWrite;
                    break;
                case vk::ImageLayout::eDepthStencilAttachmentOptimal:
                    flags = vk::AccessFlagBits::eDepthStencilAttachmentWrite;
                    break;
                case vk::ImageLayout::eShaderReadOnlyOptimal:
                    // Make sure any Copy or CPU writes to image are flushed
                    flags = vk::AccessFlagBits::eShaderRead | vk::AccessFlagBits::eInputAttachmentRead;
                    break;
                case vk::ImageLayout::ePresentSrcKHR:
                    flags = vk::AccessFlagBits::eMemoryRead;
                    break;
                default:
                    break;
            }

            return flags;
        };

        auto const barrier = vk::ImageMemoryBarrier()
            .setSrcAccessMask(srcAccessMask)
            .setDstAccessMask(DstAccessMask(newLayout))
            .setOldLayout(oldLayout)
            .setNewLayout(newLayout)
            .setSrcQueueFamilyIndex(0)
            .setDstQueueFamilyIndex(0)
            .setImage(image)
            .setSubresourceRange(vk::ImageSubresourceRange(aspectMask, 0, 1, 0, 1));

        cmd.pipelineBarrier(vk::PipelineStageFlagBits::eTopOfPipe, vk::PipelineStageFlagBits::eTopOfPipe, vk::DependencyFlagBits(),
            0, nullptr, 0, nullptr, 1, &barrier);
    }

    void update_data_buffer()
    {
        mat4x4 VP;
        mat4x4_mul(VP, projection_matrix, view_matrix);

        // Rotate 22.5 degrees around the Y axis
        mat4x4 Model;
        mat4x4_dup(Model, model_matrix);
        mat4x4_rotate(model_matrix, Model, 0.0f, 1.0f, 0.0f, (float)degreesToRadians(spin_angle));

        mat4x4 MVP;
        mat4x4_mul(MVP, VP, model_matrix);

        auto data = device.mapMemory(uniform_data.mem, 0, uniform_data.mem_alloc.allocationSize, vk::MemoryMapFlags());
        VERIFY(data.result == vk::Result::eSuccess);

        memcpy(data.value, (const void *)&MVP[0][0], sizeof(MVP));

        device.unmapMemory(uniform_data.mem);
    }

    bool loadTexture(const char *filename, uint8_t *rgba_data, vk::SubresourceLayout *layout, int32_t *width, int32_t *height)
    {
        FILE *fPtr = fopen(filename, "rb");
        if(!fPtr)
        {
            return false;
        }

        char header[256];
        char* cPtr = fgets(header, 256, fPtr); // P6
        if(cPtr == nullptr || strncmp(header, "P6\n", 3))
        {
            fclose(fPtr);
            return false;
        }

        do
        {
            cPtr = fgets(header, 256, fPtr);
            if(cPtr == nullptr)
            {
                fclose(fPtr);
                return false;
            }
        }
        while(!strncmp(header, "#", 1));

        sscanf(header, "%u %u", width, height);
        if(rgba_data == nullptr)
        {
            fclose(fPtr);
            return true;
        }

        char* result = fgets(header, 256, fPtr); // Format
        VERIFY(result != nullptr);
        if(cPtr == nullptr || strncmp(header, "255\n", 3))
        {
            fclose(fPtr);
            return false;
        }

        for(int y = 0; y < *height; y++)
        {
            uint8_t *rowPtr = rgba_data;

            for(int x = 0; x < *width; x++)
            {
                size_t s = fread(rowPtr, 3, 1, fPtr);
                (void)s;
                rowPtr[3] = 255; /* Alpha of 1 */
                rowPtr += 4;
            }

            rgba_data += layout->rowPitch;
        }

        fclose(fPtr);
        return true;
    }

    bool memory_type_from_properties(uint32_t typeBits, vk::MemoryPropertyFlags requirements_mask, uint32_t *typeIndex)
    {
        // Search memtypes to find first index with those properties
        for(uint32_t i = 0; i < VK_MAX_MEMORY_TYPES; i++)
        {
            if((typeBits & 1) == 1)
            {
                // Type is available, does it match user properties?
                if((memory_properties.memoryTypes[i].propertyFlags & requirements_mask) == requirements_mask)
                {
                    *typeIndex = i;
                    return true;
                }
            }
            typeBits >>= 1;
        }

        // No memory types matched, return failure
        return false;
    }

#if defined(VK_USE_PLATFORM_WIN32_KHR)
    void run()
    {
        if(!prepared)
        {
            return;
        }

        update_data_buffer();
        draw();
        curFrame++;

        if(frameCount != INT_MAX && curFrame == frameCount)
        {
            PostQuitMessage(validation_error);
        }
    }

    void create_window()
    {
        WNDCLASSEX win_class;

        // Initialize the window class structure:
        win_class.cbSize = sizeof(WNDCLASSEX);
        win_class.style = CS_HREDRAW | CS_VREDRAW;
        win_class.lpfnWndProc = WndProc;
        win_class.cbClsExtra = 0;
        win_class.cbWndExtra = 0;
        win_class.hInstance = connection; // hInstance
        win_class.hIcon = LoadIcon(nullptr, IDI_APPLICATION);
        win_class.hCursor = LoadCursor(nullptr, IDC_ARROW);
        win_class.hbrBackground = (HBRUSH)GetStockObject(WHITE_BRUSH);
        win_class.lpszMenuName = nullptr;
        win_class.lpszClassName = name;
        win_class.hIconSm = LoadIcon(nullptr, IDI_WINLOGO);

        // Register window class:
        if(!RegisterClassEx(&win_class))
        {
            // It didn't work, so try to give a useful error:
            printf("Unexpected error trying to start the application!\n");
            fflush(stdout);
            exit(1);
        }

        // Create window with the registered class:
        RECT wr = {0, 0, width, height};
        AdjustWindowRect(&wr, WS_OVERLAPPEDWINDOW, FALSE);
        window = CreateWindowEx(0,
            name,           // class name
            name,           // app name
            WS_OVERLAPPEDWINDOW | // window style
              WS_VISIBLE | WS_SYSMENU,
            100, 100,           // x/y coords
            wr.right - wr.left, // width
            wr.bottom - wr.top, // height
            nullptr,               // handle to parent
            nullptr,               // handle to menu
            connection,   // hInstance
            nullptr);              // no extra parameters

        if(!window)
        {
            // It didn't work, so try to give a useful error:
            printf("Cannot create a window in which to draw!\n");
            fflush(stdout);
            exit(1);
        }

        // Window client area size must be at least 1 pixel high, to prevent crash.
        minsize.x = GetSystemMetrics(SM_CXMINTRACK);
        minsize.y = GetSystemMetrics(SM_CYMINTRACK)+1;
    }

#elif defined(VK_USE_PLATFORM_XLIB_KHR) || defined(VK_USE_PLATFORM_XCB_KHR)
#if defined(VK_USE_PLATFORM_XLIB_KHR)

    void create_xlib_window()
    {
        display = XOpenDisplay(nullptr);
        long visualMask = VisualScreenMask;
        int numberOfVisuals;
        XVisualInfo vInfoTemplate={};
        vInfoTemplate.screen = DefaultScreen(display);
        XVisualInfo *visualInfo = XGetVisualInfo(display, visualMask, &vInfoTemplate, &numberOfVisuals);

        Colormap colormap = XCreateColormap(display, RootWindow(display, vInfoTemplate.screen), visualInfo->visual, AllocNone);

        XSetWindowAttributes windowAttributes={};
        windowAttributes.colormap = colormap;
        windowAttributes.background_pixel = 0xFFFFFFFF;
        windowAttributes.border_pixel = 0;
        windowAttributes.event_mask = KeyPressMask | KeyReleaseMask | StructureNotifyMask | ExposureMask;

        xlib_window = XCreateWindow(display, RootWindow(display, vInfoTemplate.screen), 0, 0, width, height,
            0, visualInfo->depth, InputOutput, visualInfo->visual, CWBackPixel | CWBorderPixel | CWEventMask | CWColormap,
            &windowAttributes);

        XSelectInput(display, xlib_window, ExposureMask | KeyPressMask);
        XMapWindow(display, xlib_window);
        XFlush(display);
        xlib_wm_delete_window = XInternAtom(display, "WM_DELETE_WINDOW", False);
    }

    void handle_xlib_event(const XEvent *event)
    {
        switch(event->type)
        {
        case ClientMessage:
            if((Atom)event->xclient.data.l[0] == xlib_wm_delete_window)
            {
                quit = true;
            }
            break;
        case KeyPress:
            switch (event->xkey.keycode)
            {
            case 0x9: // Escape
                quit = true;
                break;
            case 0x71: // left arrow key
                spin_angle += spin_increment;
                break;
            case 0x72: // right arrow key
                spin_angle -= spin_increment;
                break;
            case 0x41:
                pause = !pause;
                break;
            }
            break;
        case ConfigureNotify:
            if(((int32_t)width != event->xconfigure.width) || ((int32_t)height != event->xconfigure.height))
            {
                width = event->xconfigure.width;
                height = event->xconfigure.height;
                resize();
            }
            break;
        default:
            break;
        }
    }

    void run_xlib()
    {
        while(!quit)
        {
            XEvent event;

            if(pause)
            {
                XNextEvent(display, &event);
                handle_xlib_event(&event);
            }
            else
            {
                while(XPending(display) > 0)
                {
                    XNextEvent(display, &event);
                    handle_xlib_event(&event);
                }
            }

            update_data_buffer();
            draw();
            curFrame++;

            if(frameCount != UINT32_MAX && curFrame == frameCount)
            {
                quit = true;
            }
        }
    }

#endif
#if defined(VK_USE_PLATFORM_XCB_KHR)

    void handle_xcb_event(const xcb_generic_event_t *event)
    {
        uint8_t event_code = event->response_type & 0x7f;
        switch(event_code)
        {
        case XCB_EXPOSE:
            // TODO: Resize window
            break;
        case XCB_CLIENT_MESSAGE:
            if((*(xcb_client_message_event_t *)event).data.data32[0] == (*atom_wm_delete_window).atom)
            {
                quit = true;
            }
            break;
        case XCB_KEY_RELEASE:
        {
            const xcb_key_release_event_t *key = (const xcb_key_release_event_t *)event;

            switch(key->detail)
            {
            case 0x9: // Escape
                quit = true;
                break;
            case 0x71: // left arrow key
                spin_angle += spin_increment;
                break;
            case 0x72: // right arrow key
                spin_angle -= spin_increment;
                break;
            case 0x41:
                pause = !pause;
                break;
            }
        } break;
        case XCB_CONFIGURE_NOTIFY:
        {
            const xcb_configure_notify_event_t *cfg = (const xcb_configure_notify_event_t *)event;
            if((width != cfg->width) || (height != cfg->height))
            {
                width = cfg->width;
                height = cfg->height;
                resize();
            }
        } break;
        default:
            break;
        }
    }

    void run_xcb()
    {
        xcb_flush(connection);

        while(!quit)
        {
            xcb_generic_event_t *event;

            if(pause)
            {
                event = xcb_wait_for_event(connection);
            }
            else
            {
                event = xcb_poll_for_event(connection);
                while(event)
                {
                    handle_xcb_event(event);
                    free(event);
                    event = xcb_poll_for_event(connection);
                }
            }

            update_data_buffer();
            draw();
            curFrame++;
            if(frameCount != UINT32_MAX && curFrame == frameCount)
            {
                quit = true;
            }
        }
    }

    void create_xcb_window()
    {
        uint32_t value_mask, value_list[32];

        xcb_window = xcb_generate_id(connection);

        value_mask = XCB_CW_BACK_PIXEL | XCB_CW_EVENT_MASK;
        value_list[0] = screen->black_pixel;
        value_list[1] = XCB_EVENT_MASK_KEY_RELEASE | XCB_EVENT_MASK_EXPOSURE | XCB_EVENT_MASK_STRUCTURE_NOTIFY;

        xcb_create_window(connection, XCB_COPY_FROM_PARENT, xcb_window, screen->root, 0, 0, width, height, 0,
            XCB_WINDOW_CLASS_INPUT_OUTPUT, screen->root_visual, value_mask, value_list);

        /* Magic code that will send notification when window is destroyed */
        xcb_intern_atom_cookie_t cookie = xcb_intern_atom(connection, 1, 12, "WM_PROTOCOLS");
        xcb_intern_atom_reply_t *reply = xcb_intern_atom_reply(connection, cookie, 0);

        xcb_intern_atom_cookie_t cookie2 = xcb_intern_atom(connection, 0, 16, "WM_DELETE_WINDOW");
        atom_wm_delete_window = xcb_intern_atom_reply(connection, cookie2, 0);

        xcb_change_property(connection, XCB_PROP_MODE_REPLACE, xcb_window, (*reply).atom, 4, 32, 1,
            &(*atom_wm_delete_window).atom);

        free(reply);

        xcb_map_window(connection, xcb_window);

        // Force the x/y coordinates to 100,100 results are identical in consecutive
        // runs
        const uint32_t coords[] = {100, 100};
        xcb_configure_window(connection, xcb_window, XCB_CONFIG_WINDOW_X | XCB_CONFIG_WINDOW_Y, coords);
    }

#endif
#elif defined(VK_USE_PLATFORM_WAYLAND_KHR)

    void run()
    {
        while (!quit)
        {
            update_data_buffer();
            draw();
            curFrame++;
            if(frameCount != UINT32_MAX && curFrame == frameCount)
            {
                quit = true;
            }
        }
    }

    void create_window()
    {
        window = wl_compositor_create_surface(compositor);
        if(!window)
        {
            printf("Can not create wayland_surface from compositor!\n");
            fflush(stdout);
            exit(1);
        }

        shell_surface = wl_shell_get_shell_surface(shell, window);
        if(!shell_surface)
        {
            printf("Can not get shell_surface from wayland_surface!\n");
            fflush(stdout);
            exit(1);
        }

        wl_shell_surface_add_listener(shell_surface, &shell_surface_listener, this);
        wl_shell_surface_set_toplevel(shell_surface);
        wl_shell_surface_set_title(shell_surface, APP_SHORT_NAME);
    }

#endif

#if defined(VK_USE_PLATFORM_WIN32_KHR)
    HINSTANCE connection;        // hInstance - Windows Instance
    HWND window;                 // hWnd - window handle
    POINT minsize;               // minimum window size
    char name[APP_NAME_STR_LEN]; // Name to put on the window/icon
#elif defined(VK_USE_PLATFORM_XLIB_KHR) || defined(VK_USE_PLATFORM_XCB_KHR)
    Display* display;
    Window xlib_window;
    Atom xlib_wm_delete_window;

    xcb_connection_t *connection;
    xcb_screen_t *screen;
    xcb_window_t xcb_window;
    xcb_intern_atom_reply_t *atom_wm_delete_window;
#elif defined(VK_USE_PLATFORM_WAYLAND_KHR)
    wl_display *display;
    wl_registry *registry;
    wl_compositor *compositor;
    wl_surface *window;
    wl_shell *shell;
    wl_shell_surface *shell_surface;
#endif

    vk::SurfaceKHR surface;
    bool prepared;
    bool use_staging_buffer;
    bool use_xlib;
    bool separate_present_queue;

    vk::Instance inst;
    vk::PhysicalDevice gpu;
    vk::Device device;
    vk::Queue graphics_queue;
    vk::Queue present_queue;
    uint32_t graphics_queue_family_index;
    uint32_t present_queue_family_index;
    vk::Semaphore image_acquired_semaphores[FRAME_LAG];
    vk::Semaphore draw_complete_semaphores[FRAME_LAG];
    vk::Semaphore image_ownership_semaphores[FRAME_LAG];
    vk::PhysicalDeviceProperties gpu_props;
    std::unique_ptr<vk::QueueFamilyProperties[]> queue_props;
    vk::PhysicalDeviceMemoryProperties memory_properties;

    uint32_t enabled_extension_count;
    uint32_t enabled_layer_count;
    char const* extension_names[64];
    char const* enabled_layers[64];

    uint32_t width;
    uint32_t height;
    vk::Format format;
    vk::ColorSpaceKHR color_space;

    uint32_t swapchainImageCount;
    vk::SwapchainKHR swapchain;
    std::unique_ptr<SwapchainBuffers[]> buffers;
    vk::Fence fences[FRAME_LAG];
    bool fencesInited[FRAME_LAG];
    uint32_t frame_index;

    vk::CommandPool cmd_pool;
    vk::CommandPool present_cmd_pool;

    struct
    {
        vk::Format format;
        vk::Image image;
        vk::MemoryAllocateInfo mem_alloc;
        vk::DeviceMemory mem;
        vk::ImageView view;
    } depth;

    static int32_t const texture_count = 1;
    texture_object textures[texture_count];

    struct
    {
        vk::Buffer buf;
        vk::MemoryAllocateInfo mem_alloc;
        vk::DeviceMemory mem;
        vk::DescriptorBufferInfo buffer_info;
    } uniform_data;

    vk::CommandBuffer cmd; // Buffer for initialization commands
    vk::PipelineLayout pipeline_layout;
    vk::DescriptorSetLayout desc_layout;
    vk::PipelineCache pipelineCache;
    vk::RenderPass render_pass;
    vk::Pipeline pipeline;

    mat4x4 projection_matrix;
    mat4x4 view_matrix;
    mat4x4 model_matrix;

    float spin_angle;
    float spin_increment;
    bool pause;

    vk::ShaderModule vert_shader_module;
    vk::ShaderModule frag_shader_module;

    vk::DescriptorPool desc_pool;
    vk::DescriptorSet desc_set;

    std::unique_ptr<vk::Framebuffer[]> framebuffers;

    bool quit;
    uint32_t curFrame;
    uint32_t frameCount;
    bool validate;
    bool use_break;
    bool suppress_popups;

    uint32_t current_buffer;
    uint32_t queue_family_count;
};

#if _WIN32
// Include header required for parsing the command line options.
#include <shellapi.h>

Demo demo;

// MS-Windows event handling function:
LRESULT CALLBACK WndProc(HWND hWnd, UINT uMsg, WPARAM wParam, LPARAM lParam)
{
    switch (uMsg)
    {
    case WM_CLOSE:
        PostQuitMessage(validation_error);
        break;
    case WM_PAINT:
        demo.run();
        break;
    case WM_GETMINMAXINFO:     // set window's minimum size
        ((MINMAXINFO*)lParam)->ptMinTrackSize = demo.minsize;
        return 0;
    case WM_SIZE:
        // Resize the application to the new window size, except when
        // it was minimized. Vulkan doesn't support images or swapchains
        // with width=0 and height=0.
        if(wParam != SIZE_MINIMIZED) {
            demo.width = lParam & 0xffff;
            demo.height = (lParam & 0xffff0000) >> 16;
            demo.resize();
        }
        break;
    default:
        break;
    }

    return (DefWindowProc(hWnd, uMsg, wParam, lParam));
}

int WINAPI WinMain(HINSTANCE hInstance, HINSTANCE hPrevInstance, LPSTR pCmdLine, int nCmdShow)
{
    // TODO: Gah.. refactor. This isn't 1989.
    MSG msg;   // message
    bool done; // flag saying when app is complete
    int argc;
    char **argv;

    // Use the CommandLine functions to get the command line arguments.
    // Unfortunately, Microsoft outputs
    // this information as wide characters for Unicode, and we simply want the
    // Ascii version to be compatible
    // with the non-Windows side.  So, we have to convert the information to
    // Ascii character strings.
    LPWSTR *commandLineArgs = CommandLineToArgvW(GetCommandLineW(), &argc);
    if(nullptr == commandLineArgs)
    {
        argc = 0;
    }

    if(argc > 0)
    {
        argv = (char **)malloc(sizeof(char *) * argc);
        if(argv == nullptr)
        {
            argc = 0;
        }
        else
        {
            for(int iii = 0; iii < argc; iii++)
            {
                size_t wideCharLen = wcslen(commandLineArgs[iii]);
                size_t numConverted = 0;

                argv[iii] = (char *)malloc(sizeof(char) * (wideCharLen + 1));
                if(argv[iii] != nullptr)
                {
                    wcstombs_s(&numConverted, argv[iii], wideCharLen + 1, commandLineArgs[iii], wideCharLen + 1);
                }
            }
        }
    }
    else
    {
        argv = nullptr;
    }

    demo.init(argc, argv);

    // Free up the items we had to allocate for the command line arguments.
    if(argc > 0 && argv != nullptr)
    {
        for(int iii = 0; iii < argc; iii++)
        {
            if(argv[iii] != nullptr)
            {
                free(argv[iii]);
            }
        }
        free(argv);
    }

    demo.connection = hInstance;
    strncpy(demo.name, "cube", APP_NAME_STR_LEN);
    demo.create_window();
    demo.init_vk_swapchain();

    demo.prepare();

    done = false; // initialize loop condition variable

    // main message loop
    while(!done)
    {
        PeekMessage(&msg, nullptr, 0, 0, PM_REMOVE);
        if(msg.message == WM_QUIT) // check for a quit message
        {
            done = true; // if found, quit app
        }
        else
        {
            /* Translate and dispatch to event queue*/
            TranslateMessage(&msg);
            DispatchMessage(&msg);
        }
        RedrawWindow(demo.window, nullptr, nullptr, RDW_INTERNALPAINT);
    }

    demo.cleanup();

    return (int)msg.wParam;
}

#elif __linux__

#if defined(VK_USE_PLATFORM_WAYLAND_KHR)
static void handle_ping(void *data UNUSED, wl_shell_surface *shell_surface, uint32_t serial)
{
    wl_shell_surface_pong(shell_surface, serial);
}

static void handle_configure(void *data UNUSED, wl_shell_surface *shell_surface UNUSED, uint32_t edges UNUSED,
    int32_t width UNUSED, int32_t height UNUSED)
{
}

static void handle_popup_done(void *data UNUSED, wl_shell_surface *shell_surface UNUSED)
{
}

static const wl_shell_surface_listener shell_surface_listener =
{
    handle_ping,
    handle_configure,
    handle_popup_done
};
#endif

int main(int argc, char **argv)
{
    Demo demo;

    demo.init(argc, argv);

#if defined(VK_USE_PLATFORM_XLIB_KHR) && defined(VK_USE_PLATFORM_XCB_KHR)
    if(demo.use_xlib)
    {
        demo.create_xlib_window();
    }
    else
    {
        demo.create_xcb_window();
#elif defined(VK_USE_PLATFORM_XCB_KHR)
        demo.create_xcb_window();
#elif defined(VK_USE_PLATFORM_XLIB_KHR)
        demo.create_xlib_window();
#elif defined(VK_USE_PLATFORM_WAYLAND_KHR)
        demo.create_window();
#endif
    }

    demo.init_vk_swapchain();

    demo.prepare();

#if defined(VK_USE_PLATFORM_XLIB_KHR) && defined(VK_USE_PLATFORM_XCB_KHR)
    if(demo.use_xlib)
    {
        demo.run_xlib();
    }
    else
    {
        demo.run_xcb();
#elif defined(VK_USE_PLATFORM_XCB_KHR)
        demo.run_xcb();
#elif defined(VK_USE_PLATFORM_XLIB_KHR)
        demo.run_xlib();
#elif defined(VK_USE_PLATFORM_WAYLAND_KHR)
        demo.run();
#endif
    }

    demo.cleanup();

    return validation_error;
}

#else
#error "Platform not supported"
#endif